It's kind of funny really.
My girl of 4 years and some change left me back in February and while I am a lot better now, though we are unfortunately done forever, I was a wreck for a few weeks there.
Anyways, my brother has been through this and he gave me the best advice to ensure that you act "normal" infront of your ex. Guys, and girls presumably, spank your monkey like right before you see her, call her, e-mail her, etc.
I just did almost four weeks of no contact only to blow it all by crying on the phone tonight and calling her back too late sobbing like a weak douchbag. If I had just choked my chicken and achieved the "enlightened" sense of euphoria that accompanies whacking off, I would have been able to maintain my composure, and not feel like such a moron right now.
Crying is not attractive, it only guilts them, which doesn't get her back to you at all.
So if you are crying while you dial her number, writing up a 10 page "I still love you" letter, or putting together a 20k e-mail with some Browning poetry or whatever, stop it and get on this here interweb and take care of some bidness first. Hey it's all out there, no matter what you tastes are sailor, for free no less.
Then put down the phone, trash the letter, and delete that monster e-mail. Trust me, it wouldn't have worked anyway, I know from experience.
But if you must have poetry, here's a little couplet to help you stay cool in front of her the next time you see her:
If you want to get her back,
before you talk, take time to jack.
Good luck!