Graphics - High quality graphics convey a message to the reader. Try to make your banner professional and make it stand out. Curiosity - Generates interest in the site behind the banner. Ask a question or tell a riddle. Don't overdo it though.
Moderation is the key.
Simple Text - Make your banner clear and concisive. Don't overcrowd the banner with too many messages. Keep it simple but effective. Another way to generate extra traffic is through announcement sites. These sites exist on the Internet with the sole purpose of announcing new sites to the online community - useful for Webmasters and marketers to promote their new products.