- Work in different browsers (not only FireFox :) );
- The page content must be centre of user attention;
- No changes in current theme atmosphere;
- The site navigation must be simple and clear (It is very strange when the main navigation placed over the body and below the title);
- Separate top section (The top of the screen (the main branding & main nav area) must be distinct from the rest (the main content).
- The advertising banners must not be placed together (If they do than smaller adv. banner will not "work");
- No underlined links (Just try to read "Browse categories page" page with lot of underlined links :), links must be similar;
- Much whitespaces makes blocks of text more readble;
- Site must to have big text (important elements must be bigger than less important elements);
- The page must be divided into clear sections, and there must be highlighted important elements.
- Design must be good looking :)
And... "Use as few features as are necessary to achieve what you need to achieve"!
It was hard to create design with all features writted over but: