This is what I do:
1. Ccry. Lots. But only when I'm alone because I don't need pity, that just makes me feel worse.
2. Have fun with friends and bitch occasionally but not too often because the friends will probably get annoyed, but they do understand what you're going through and will let you do some bitching.
3. Go shopping (man, I love retail therapy).
4. Realise what a waste of time he was (this can come at any stage after 1 but usually occurs at this point).
5. Get a new guy (ONLY when you're absotively posilutely sure you're over him, otherwise it's not fair to the new guy).
Time may or may not play a part in some or all of these events. Haircuts can help, but I didn't need one for the last one - even though it was the worst, I got over it fastest (weird, huh?).