When I do my advertising ads I make sure it is
1. Looks professional like a company ad meaning it has to appeal to my eyes first
2. No spelling errors
3. KISS - Keep it Short and Sweet ( too much is a turnoff)
4. Has all the important information there
5. Leave some up to the imagination, let them be curious enough to want to click the ad
Ex...
Work From Home, Be Your Own Boss
For More Details Please Click Here
http://www.sfimg.com