Bannerflow Blog Display advertising best practices - ultimate guide

Explainers | 12 min read

Display advertising best practices: ultimate guide

Display advertising best practices do not stand still, they change and evolve constantly. And in the world of online display, keeping track of these changes is a necessity.

Why you ask? Well, banner best practices have changed much since the very first online banner ad appeared in the 1990s. From humble beginnings, display advertising has gone from simplistic static images to a key channel of digital marketing. It now incorporates a whole spectrum of technologies from rich media ads to video – not to mention programmatic buying and dynamic creative optimisation (DCO).

Plus, with the growth of programmatic digital out-of-home (DOOH) networks, and digital video, how display advertising interacts and is produced alongside these different channels is set to get ever more important.

Simplifying production and maintaining best practices

Producing display campaigns isn’t easy though – especially if you have multiple production layers. Even if you produce display advertising campaigns in-house, you will still need to cooperate with a variety of external services. Knowing what to do and how to do this is an important part of creating and publishing display ads without complications.

Indeed, when working with these external factors, it is necessary to put in place display advertising best practices. What’s more, many advertising networks have their own best practices and guidelines. Any ad you want to serve using a chosen network must follow these rules. Knowing what they are is key: from font size to video playback.

But what are the latest display advertising best practices? And how can you achieve approval by ad networks, and be engaging for viewers?

Mobile first

Ok, stop everything! You’ve been making banners all wrong. Yes, really. The truth is your beautiful display ad – made desktop-first – is far more likely to be viewed on mobile. According to eMarketer research views of mobile display ads now outpace desktop by quite some measure. For example, recent figures show that 70.3% of all display ads in the US are mobile ads, compared to 29.7% for desktop.

The message is clear: now is the time to design everything mobile first. Mobile first, or responsive web design is a trend that will continue too. Remember, Google now index mobile sites first, ranking them above sites that aren’t mobile friendly – banners that aren’t responsive are dead.

Therefore, throw out the old thinking of designing a campaign desktop first and then scaling down. Scale up from mobile! Advertising has long gone mobile and now banner designers must think as much.

General display ad best practices

The Internet Advertising Bureau (IAB), companies, and ad networks have developed a range of display ad best practices for banner advertisers to follow.  In particular, the IAB has released an ad portfolio on how to best produce banners across devices, which can be found here.

Indeed, before building any display campaign, it is always worth checking the exact requirements you need to hit in order to serve your ads. The networks and publishers you use will always require you to follow their exact requirements – do this and you will make sure that approval for your campaigns is quick and without hassle.

Some of the below points are guidelines but most ad networks and publishing platforms follow them religiously:

Border requirements

In its display ad guidelines, the IAB states that display ads should be “distinguishable from normal webpage content”. It also stresses that the “ad unit must have clear defined borders and not confused with normal web content”. This best practice is required by ad networks too. Follow this rule so as to get swift ad approval.

The simplest way to tick-off this piece of best practice is to make sure your display ad has a border. In addition, make sure your ad creative doesn’t blend into the background. Both this, and the use of a border, should be part of all your banner designs, always.

Avoid fraudulent simulations

This should be obvious: do not include fake computer simulations that could knowingly (or unknowingly) confuse viewers in your ads. You can add fake sounds to the major things to avoid too – or anything that makes your banner feel like a computer notification.

This is important as it not only stops malicious advertisers, and potential ad fraud, but it protects your brand’s reputation. Brand safety and transparency cannot be ignored! They are key concerns of both viewers and digital marketing teams alike.

Creating display ads that mimic computer actions is unprofessional and dishonest. And such “scareware” is often associated with rogue advertisers. Avoid at all costs.

Genuine interactivity

Interactive HTML5 display ads are now mainstream. Yet, if you want to include interactive features in your display ad, make sure the interactivity is genuine. Don’t make a banner ad that appears interactive in a bid to increase your click-through rate.

Take the time (and effort) to code, or use HTML5 widgets, which provide the viewer with genuine interactivity. Fail to do so and you harm others in the industry taking the time and effort to make engaging banners.

Animated banners

Some networks have a max loop length for animated HTML5 banner ads. Always check the networks and publishers you are using to make sure all your ads comply with their regulations.

The IAB recommends that any animation must not exceed 15 seconds in terms of length. They also recommend to avoid flashing, high contrast, fast moving or bright coloured animations. Again, while this may gain a viewer’s attention, it is poor design, and reflects poorly on the brand advertising that uses such techniques.

Fallback images

Many networks require fallback images. These are static or .gif versions of your display advertisements. The reason for this is simple: it’s in case your display ad finds itself on certain (usually older) devices which cannot show HTML5.

Fallback images are especially important for heavy creatives such as video and rich media, where device load speed can be an issue. Take the time to pay attention to the fallback image – it might be the first thing a viewer sees in some cases.

Creating fallback images is an automatic feature in some creative management platforms (CMPs), for example, Bannerflow. It’s one less thing to think about when creating awesome display ads.

Video banners

Video banners and digital video is now an important part of marketing mix. Indeed, according to eMarketer research, the most popular types of rich media ad is now out-stream video —that is, ads that play outside of other video content, such as between paragraphs of text—and in-feed premium video ads on social platforms.

As well as making awesome backgrounds, using them as part of the animation within a display ad is increasing due to greater user engagement. There are of course best practises when using video – load time being an issue. According to the IAB, for auto play video banners – like animated banners – the max duration should be 15 seconds. While the recommended max file size should be 1.1mb and 24fps – for lower bandwidths 18fps is allowable.

For videos that are user initiated the duration of the video is less of an issue, but the rules for fps remain the same. Remember, even when auto-playing, the default setting for any sound should be mute. Likewise, the video ad must not expand, unless initiated by the user. Remember, you want to engage with viewers, not annoy them!

Monitor script size

Another critical  banner element to consider is script size. Monitor and optimise the “weight” of each and every banner in a campaign. This can be an especially horrible repetitive design task if you do not use an ad builder tool and cannot copy banners easily.

The reason for doing is simple: not all kb’s come from where you think (images, fonts, and animation, etc.). What’s more, sometimes the heaviest part of the total weight of a HTML5 banner, is tracking scripts. Occasionally these alone can weigh more than 100 kb! These scripts normally come from your ad server too. Therefore, if you regularly have problems with your banners being too heavy, then don´t forget to check the scripts!

Best practices to increase CTR and conversions

Once you have applied the requirements set by your advertising network, and optimised your display ads, you can move on to the next stage of your campaign. This means applying best practices to help you produce and run display advertising campaigns that convert.

Personalised advertising

Marketers and advertisers are able to customise all parts of their buyer’s journey, making offers personalised. And this this is mainstream within display advertising too.

One thing to consider when producing a display ad campaign is using the majority of your display budget for networks or exchanges that have high-quality inventory. Or allow you to easily target your ideal customers. Having a good media buying agency or a member of the marketing team with this competency, in-house, is a major plus.

Moreover, studies have shown that relevant or personalised advertising is far more effective than general advertising. For example, users are more likely to click on your ads if they think they are useful. It is always better to show a relevant ad in the most relevant space.


Retargeting campaigns are effective and proven types of display advertising campaigns. But what is retargeting? It means directly targeting display ads to those customers who have already been to your website but have not converted. Retargeted display ads often have a higher click-through rate too. This because they are targeting those who have already expressed an interest in your brand.

Yet a word of caution. With GDPR now inforce in the EU, other countries adopting similar legislation, and ePrivacy on the horizon, rules around cookies are in constant flux.

With GDPR in particular, a lot is untested. For example, there are still questions over how it will be implemented long-term. Plus, questions – still – on how consent should be gathered and shared.

Therefore, display advertisers must be careful. It is well worth finding out what your preferred advertising networks, media buyer, or ad tech provider is doing in regards to retargeting. This is because the time a tracking cookie can remain active (and retargeting is effective) is about to vary widely.

The truth of the matter is that – like all best practices – you need to treat the user with respect. Retargeting is great but use it responsibly. For example, once your viewer has converted make sure you don’t continue to retarget them!

Dynamic content and using data feeds

A word of advice: take personalisation and relevancy to the next level with dynamic content display ads. Dynamic ads are HTML5 rich media ads that use data feeds to supply updating data into already published display ads. These updates are fast and regular, and can be performed every 15 seconds. These ads are particularly good for sports odds, and e-commerce stores but potential applications are endless.

By using this technique, you can always make sure that your display campaigns are relevant and up-to-date. If you have a product inventory, sell holidays, or are a currency exchange you should be using dynamic content. It will increase both your relevance and your click-through rate. It’s also easy to set-up if you have the right ad tech like a creative management platform. Plus, there are many different types of dynamic strategy too: read about them, here.

However, always get the basics right

Ok, first things first, it’s worth taking the time to get the fundamentals of your ad right first. Short, catchy copy, sharp imagery, and a solid call to action are solid foundations for even the most basic of ads. Read what industry experts recommend, and focus on how display advertising design uses copy, and CTAs. You need to excite interest and offer something to viewers that makes them want to click-through.

One tip: the CTA should always be strong and eye-catching. The best way to achieve this is by using a button. Making sure it is eye-catching, is one way of encouraging a viewer to click-through. Basic yes – but you’ll be surprised how often it’s overlooked and leads to poor conversion.

Test copy, call to actions (CTAs), or everything!

However, the surest way to improve CTR – even in basic ads – is by constant testing. Find the best creative by testing different ad variations. If a banner designer can see and use analytics to optimise ads within a marketing team, it’s easy to A/B test and produce better copy and CTA’s that convert. Not only that but you can apply A/B testing to every element in a banner from position of logo to video playback options and imagery.

Oh, and a brief mention on A/B testing best practice: it should always be based on post-view conversions. Plus, always remember to keep the audiences separate.

And another word of advice, if you build your banners manually ignore all of the above – it’s not worth it. You’re asking too much for any one person.

Yet, for those of you reading this who use a CMP, then this is all fairly simple to undertake. Your CMP and its DSP integrations should allow you to update already published banners and apply improvements in real-time. Plus, combined with easy production tools, such as scaling, making the variations required is easy.

And finally… dynamic creative optimisation (DCO)

One way to ensure personalised advertising, or indeed, “hyper-relevant” data enhanced advertising, is by using dynamic creative optimisation. Oh, and by the way, it incorporates all of the above and the best practices from easier in the article.

It’s a combination of technologies (DMP, DSP, CMP, etc…) that banner creators will hear more and more of. Indeed, it’s application among display advertisers is happening at a rapid rate. Therefore, it’s something that’s worth reading about in its own article, which handily enough, can be found here.

Next steps

Planning and executing a display campaign is easier than it has ever been. Follow the best practices we have described and you’ll be in a better position to produce remarkable banner campaigns.

Remember, display is in constant flux and open to rapid change. In-house marketing is growing all the time. Plus, more teams are using CMPs to build their display campaigns minus agency assistance.While, dynamic creative optimisation is becoming mainstream. Expect display ad best practices to further evolve and marketing team competencies to change with them.

Want to know more about you can improve your display ad campaigns?  Read our blog posts, get in touch, or request a demo of the Bannerflow creative management platform.

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