How to effectively run split testing of Adwords campaigns

As a rule, I would ignore the conversion rate comparison of different adverts unless the adverts appealed to different people. If you are comparing "Buy xxx Today" and "Buy xxx Now", the people who click on it are likely to be the same, but you'll have to wait ten times as long to see if there is a difference in the conversion rate, rather than the clickthrough rate.

It all depends on what you're doing with your split-testing, I suppose. If you are trying to improve your clickthrough rate, without changing your target market, you can probably focus on clickthrough rate (as long as you're careful). If you are trying to entice more people by changing the target (e.g. by using words like "cheap" or "quality", or highlighting different benefits or product features), then you need to watch clickthrough rate, conversion rate and (if possible) conversion value.


EDIT: Just re-read that, and I want to make it clear, that I don't sell kisses. I'm not that kind of boy!