Choose the One Thing to Notice First
A banner has a small window to make its point. Decide what the viewer must notice first: a benefit, event, product, image, or action. Give that one element the strongest contrast or space. A secondary detail can support the message, but it should not compete with it.
Write the promise in one plain sentence before choosing effects. A banner that tries to announce a launch, explain a feature, list three benefits, and ask for a click has no clear first glance. Remove the work that belongs on the page after the click.
