Here is a quick summary for those of you who don’t want to read the whole article:

1. Always use strict doctype and standards-compliant HTML/CSS
2. Always use a reset at the start of your css
3. Use -moz-opacity:0.99 on text elements to clean up rendering in Firefox, and text-shadow: #000 0 0 0 in Safari
4. Never resize images in the CSS or HTML
5. Check font rendering in every browser. Don’t use Lucida
6. Size text as a % in the body, and as em’s throughout
7. All layout divs that are floated should include display:inline and overflow:hidden
8. Containers should have overflow:auto and trigger hasLayout via a width or height
9. Don’t use any fancy CSS3 selectors
10. Don’t use transparent PNG’s unless you have loaded the alpha

But you should go ahead and read the whole article (via WebAppers.com).