First of all, you should carefully choose the advertisement space provider – the site where you will place your banner. The content should be somehow connected to the topic of your site, the one advertised through banner. This will increase number of clicks at the banner, as users will be interested in the topic.
As soon you have chosen host web-sites, it is time to consider the type of the banner to use. This depends on your expectations. In case you would like just to remind of your site a simple 88x31 “button” would do. But if your purpose is immediate attention to discounts or a new product sold through your site, a Flash pop-up banner is probably the best choice.
Only now it is time to think of the design. You can choose the most extravagant one, experiment with different color schemes, use animation, of course. There are no strict rules in designing the banner, but do not exaggerate, your banner is a business card of your site, remember it.
Additionally, when thinking of a design do not forget – the main purpose of banner is to inform the visitor in two-three words about your web-site. This means, whatever you do with the banner, just make sure that info is accurate and clear. Visitor won't admire your banner longer than a second or two – he must be able to perceive info immediately.
Finally, I can propose you a simple test to find out whether banner you made or ordered is efficient. Ask anyone near you, better a not very advanced user, to take a quick look at the banner, and see whether he/she can say what it is advertising. If yes, your banner works.
