To celebrate Google’s 7th birthday, the AdWords Blog posted their top 7 tips:

1. Identify your goals
2. Build a relevant, targeted keyword list
3. Use the right keyword matching
4. Organize your campaign
5. Write clear, compelling ad text
6. Choose useful destination pages
7. Track results frequently and modify your campaign

Another good place to start is the Marketing Training Center from TruthMedia.

Jerry also offers an interesting take on AdWords.