This is just a quick easy tip...
Don't just look at your site in Internet Explorer and think all is well. Download, at the very least, Firefox (SeaMonkey, Netscape, some other Mozilla based browser, etc) and check your site. You might be shocked at how your page looks in one of these browsers.
Browser stats
Plus - if you are going to be doing any website work, Firefox has some great developer addons that could be extremely helpful for you.
If you're interested -
http://www.mozilla.org/