Rule #10 - Make your pages error-free

Make sure your graphics load. Make sure that your links work. Where you link pages at other sites, review your links regularly to catch sites that have moved.

Validate your pages. Errors in your HTML can cause strange behavior, including information that doesn't display.

Look at your pages. It's truly amazing to see a page that doesn't even load correctly; it says that someone didn't care enough to look even once before putting that page on the web. While you're looking, make sure that the page displays the way you intended for it to display. Do this in several browsers; not all browsers implement the same tags, or implement them the same way. Browsers also tend not to follow HTML syntax faithfully; validation is no guarantee that any particular browser will render your page in a readable, useful manner.