Here's an excellent tip for browser compatibility, as well a SEO and Usability. Download a text based web browser, such as Lynx, and add it to your testing suite (a set of browsers you have for testing purposes. If you don't do this, please do so!). This will make creating inter-operable websites so much easier, as text based browsers aren't as forgiving as others, and thus, when you make it work with it, it will likely work with everything else. Sure, it won't display your images, flash animations and other stuff unique to graphical browsers, but its definitely worth it if you want more success and to be taken more seriously. Search Engines don't use graphical browsers, but rather they use text based ones, so if your website shows up properly in one, it will show up properly in a search engine.