Research your topic, and see what other successful sites are doing with the same topic. Figure out why the other sites are successful. This may give you ideas on what you'd like to do with your site. Make your pages recognizable by designing a logo which you can put on every page for your site. Proof read and spell check your site.
Spelling mistakes can give bad impressions.
Ensure that navigating from one place to another requires less than four clicks. Sound navigation will ensure a friendly response from visitors. Avoid having long pages of text. Keep everything to the point. If it looks like something is going to take time and require a lot of attention you can forget about it.