A successful banner has excellent copy. Be sure to spend ample time thinking about what would interest the surfer. Another rule of thumb for good copy is to keep it short and simple. The text should support the banner punch line and should be informative and practical, making the viewer curious or bringing out a smile. Preferably, the copy should end with the same catchy phrase as on your web site unless the banner punch line is the same.

The ideal file size of a web banner is 10kb or less - the lesser, the better. The reason is simple. Since banners are generally displayed at the top of web pages, they should load before or with the main page text and grab the viewers' attention immediately. However, decreasing the file size of banners leads to tradeoffs in animation and the number of colors used (in animated gif banners).