The Google AdWords team built A/B split testing right into the AdWords interface, allowing you to test ad variations for the same keyword at no additional cost. Be sure to only modify one element of your ads for testing. Changing more than this will make it impossible to know which changes generated which results! The Ad Text Report will compare impressions, click-throughs, CTR, conversions and conversion rate across your ad variations allowing you to determine the most effective ad copy. Gradually, you can perform this same optimization over each element of your PPC ads. The rewards are obvious: a higher CTR will reduce your PPC costs!