Couple of things-Vaseline above the eyes will help to keep sweat out of the eyes. This is apparantly what Sean Kelly does.

And the Foreign Legion cap with the tail down the back. Really usefull for those long rides where you have the sun at the back of the neck for extended periods. I use the bandana as a Scarf for that tender spot that normally would never see much sun until you hunch down over the bars for extended periods