Dude, I'm totally with you. My problems are DEFINITELY related to thinking too damn much before a social encounter. What HenryHill said was golden: Follow the 3-Second Rule; don't give your mind time to think. Besides that, here's a few tricks that help me a little bit:
1) Get to the event early. That way, it's just you, the host, and one or two other people....much easier to approach a single stranger or two versus walking into a crowded event and not knowing anyone.
2) Grab a tray of food, approach a small group and say, "Wow! Have you tried these little things? They're great! This sounds silly, but I have no idea what they're called....help a brother out?" Learned this cheesy little trick about two months ago. Works, but if you're chunky, it might be considered a DLV....just saying.
3) Don't self-medicate the problem, even with alcohol. I've tried with Valium and other meds for years and they don't fix the problem, they just sweep it under the rug temporarily....it always comes back. If you want to fix anxiety for good, you've got to face up to it sober like I'm doing right now, and without resorting to "liquid courage".