If you have links to large graphics, audio or video files, tell the user how big the file is so she can decide whether she has time to download it. Don't design your page too wide. Many users have monitors which only display 640 pixels wide. It's not nice to force them to scroll. Try not to make your page too long.
Web surfers hate to scroll down, too.
Some combinations of text and background colors can be completely unreadable by people with color blindness. Maroon backgrounds seem to be especially difficult to use successfully. Different computer monitors will display the same color differently. A maroon background can be displayed as a range of colors from pink to black, depending on the monitor used. It's best to stick to a plain, light background with black text.