The first thing you want to make sure of is that your account is properly set up. This simply means having all of your keywords grouped by the common keyword method that you can learn here at WA.

Instead of going through the exact details, go read my tutorial on Conquering the Google Slap.

You can read it here: http://my.wealthyaffiliate.com/share_zone/view/169

This will provide the information regarding dealing with the google slap and proper keyword grouping.

Also, you can check out the Learning Center tutorials regarding:

Writing good ad text,
Proper keyword grouping
and the Case Studies on google.

Once you are comfortable with these topics, it's time to move on to the most important aspect of sky-high CTR's:

Ad Copy.