jeffreyf posted an instructable for how to tie a Four in Hand and his own knot, but didn't cover the Half Windsor or Full Windsor. Since all of these knots use many of the same moves, I'm including a Four in Hand in this series.
The pattern to remember is "Over, Under, Around, and Through".
Step 1: Ready?
Step 2: Over
Step 3: Under
Step 4: Around
Step 5: Through
Step 6: Tighten
Then bring the knot up to the collar by pulling up on the knot while you pull down on the narrow tail.
Repeat these two motions as necessary.
Step 7: Finish
Step 8: Dress Down
Loosen the knot. Undo a button or two. Have a beer.