I personally prefere non-frame approach as it allows the user to bookmark individual pages. But some customers may request this feature to be avoided, then you may look for frame version. Colors Choose max three colors, or two colors which you base your design upon. Avoid to work with more than three colors, otherwise designing gets very complicate. Keep email-addresses hidden if you do a site with a lot of people, you will regret it later.
Good solution is to use a CGI-based feedback form.
In general less important information as people usually won't scroll til the end of a page, but when they do that they realize they reached the end of a page. Visit the Graphic Lab to check some resources for the design part of your site. Well, this is the biggest hassle. Check the Dynamic HTML resource section and realize how cumbersome it gets when you start to really use all features of the browsers. In general, use as general methods as possible.