To become a good advertising campaign, first of all, has to sell its product. So the first thing it has to do is eye-catching. Something like a big red spot on a bright green background or something that's so funny the audiences will feel rewarded for looking at the piece. Of course different types of advertisement will work on different kind of media. For example a simple and eye-catching advertising would work great on a billboard, since the drivers on the road can quickly identify the product. On the other hand an advertisement on a magazine can have more details than a outdoor advertisement.
I didn't take an advertisement class until my final semester since my major is illustration, but most of my other graphic design projects did involve advertising since it plays a big role in the graphic design industry. Here's a list of designs:

1. Chapters out of home ad
2. Pollution Probe magazine ad
3. OXO multimedia ad