1) People Want A Social Life
Offer your visitors a free community. People like to have a place where they can have discussions with others on a particular subject. You could even create multiple online communities. For example, if you were selling gardening tools, you could have a message board to discuss gardening tips and a chat room about picking the right gardening tool.
2) People Want
New Information
Supply
news stories related to your site. People want current news on the
topics they are interested in. You could also include new "how
to" articles.
For example, if there is a hot or popular news story going on, you
could somehow relate it to your web site's theme.
3) People Want
Enjoyable Experiences
Allow your visitor's experience to be an enjoyable one at your web site. Provide easy navigation, fast loading graphics, search options, etc. You could offer online games that are related to your web sites theme. You could offer prizes to the highest scorers too.