The performance of an ad is measured by looking at the ratio between the number of ad displays and the number of clicks.
To increase the performance of your advertisement you need to increase the number of people who click on it.
To increase the number of people who click on it there are two steps to follow:
Attract attention with an image or a video
Make you want to know more with a powerful text
Attract attention with an image or video
The main way to attract attention is to use an image (or video) that "stops the scroll".
That is to say, an image that will intrigue or catch the eye so much that the person who sees it will give it a few moments of attention to try to understand what's going on.
How to stop the scroll
Several techniques are possible. Remember that here you have only a few seconds to decide the user to stop scrolling.
Social networks have fairly neutral background colors (cream, midnight blue, black). So use images that stand out against these background colors.
Use images with multiple bright colors within the same image.
Do NOT use pictures that are too "database". It's better to have a nice authentic photo taken with your smartphone, than an umpteenth smiling woman's face, totally stereotyped and that nobody believes in anymore.
Use bold text (sparingly) to emphasize an essential aspect of your product.
Use a 1:1 aspect ratio (i.e. a square image). Why should I use a square image? Because it is the format that takes up the most space on your user's screen.
For videos you can use a blur effect on your image during the first 2 seconds. Indeed on instagram the images are blurred the time they load and users are used to waiting when they see this blur, the time to see what it hides. By using this blur effect intelligently you will be able to stop the scroll because your audience will have the "instagram reflex".
Directly highlight the product/service and the expected benefit.
For videos: keep them short (15 seconds is ideal).
Then, once the attention is captured, it's the text's turn to do its job.
Make you want to know more with a powerful text
Once the person stops scrolling and gives you his or her attention, you need to get the person's interest.
To do this your text can :
Use mystery: A locksmith reveals his technique to open all doors with a train ticket
Ask a question: Are you locked out? Our team can intervene within 15 minutes
Describe the benefits of your service/product
Intrigue the reader
Use a key number: 14 techniques to open your door without a locksmith
Use the news: January 21, 2021: here's what will happen
In any case, the one and only purpose of your text is to push the person reading it to click on your ad to see what's behind it.
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Finally, keep in mind that it is absolutely normal to have to perform several tests before finding an ad that excels.
So there's no need to worry, you'll improve as time goes by!