First, create two or more ads within the same Ad Group. Try out different headlines or highlight different offers—the sky’s the limit. Our automatic ad optimization will then show ads with a higher clickthrough rate (CTR) more frequently. The served percentage number, located under your other ad statistics in each Ad Group, will show you how often each ad is being shown. You can then refine the text of ads which are being shown less often, or delete them from the Ad Group entirely. To make sure you have this feature enabled, follow the instructions here.
Testing the (ad text) waters
Want to test out different ads, but not sure how to compare their performance? Here’s a tip from Emel M., an AdWords specialist:
