Mobile ad creative and messaging have a major impact on the effectiveness of a mobile advertising campaign. This means testing and refreshing are crucial. Here are five best practices for putting together mobile ad creative, in addition to blind data to show how ad creative makes a difference: 1) Keep messaging simple: if a user can’t understand a mobile ad within two seconds, your messaging needs to be simplified; 2) Provide value in your call-to-action: use straightforward descriptions in the form of a graphical button; 3) Imagery and screen captures: consumers are more likely to download an app is they can visualize how it will benefit them; 4) Timing is everything: take advantage of seasonal and time-sensitive trends; 5) Use A/B testing to test creative messaging and copy: constantly measure and compare your results, then iterate on-the-top performers. (ClickZ)