* Avoid using Alpha-PNGs. Instead use GIFs especially build for a certain background-color.
* Avoid relying on max-width, min-width
* Avoid using widths in combination with margin, padding. Instead use one element for the width and another element for margin & padding

Most of the times I end up with a small extra-stylesheet with some separate IE-styles included via Conditional Comments.

This said: On my personal site I ignored some restrictions of the Internet Explorer - guys with standard-compliant-browsers get a far better site.