Use a call to action

Non-web advertising such as TV or radio is not as interactive as web-based advertising such as advertising banners. With TV or radio, the audience has to only watch or listen. Banner advertising is fundamentally different in that the visitor is required to click on the banner. So when visitors see a banner, they need to be explicitly told that it is intended that they click on it.

Placing a call to action such as "Click here!" or "Submit" or "Sign up now" on a banner is one of the easiest ways to significantly improve the CTR.