10 Tips to Test in Your Ads
1) Include www in the display URL
2) Include a keyword on each line of your Ad
3) Include a keyword or promotion at the end of the display URL
4) Include numbers and special characters such as # $ % & * + =
5) Add ! after a call to action
6) Include the word "free"
7) Include exact price of a product
8) Include a special promotion such as a coupon code, free shipping or sale
9) Stress urgency - today, now, limited time offer, etc.
10) Capitalize most words in your ad text
Taken from SphinnCon 2010 / J-Town Productions Ltd.