And what is that, well, write clean HTML code. Check out HTML Tidy for a great tool to cleanup the mess you call a webpage (at least from a coding standpoint)

Link to an easy to use version:
http://dev.int64.org/htmltrim.html

Tools for you Firefox users:
HTML Validator (includes Tidy)

Check out these posts too:

  1. CoffeeCup Free HTML Editor better than NVU
  2. New version of Firefox out today (v1.5.0.3)
  3. How to clean the HTML code from Word
  4. Take Your HTML Tables to a New Level with JavaScript Frameworks
  5. Crawling through HTML forms
  6. Are you brave enough for Firefox 1.5 RC2
  7. Real-time HTML Editor