I know what you mean. I got a job as a sales consultant a couple of years back and was trying to sell things that people don't need to, well, people. I was always nervous speaking to my first customer but after that I was fine, even if they were scary looking.
That job really helped me come out of my shell, and I feel you're in the same boat - there are still some nerves there but not nearly as bad as I used to get... I was a shy motherfucker up until I started that job and I don't even know why I took it in the first place because I was scared shitless of talking to people! Nowadays though I'm comfortable talking to groups, I enjoy giving presentations and I do much better in interviews etc... but fast forward to today and into the world of PUA and I find that I always get nervous before opening my first set. It's exactly the same scenario when you think about it, I mean after I open that first set and see that they're not evil then it just comes naturally to open other sets after that. People are fantastic and they all have stories to tell - you should be fascinated by them, not afraid!
What I think will work for you is to just go open a set and talk to everybody, shift eye contact between all of them while talking so your attention is well balanced. Your goal here is not to lock them in and close them and all that stuff, just throw in a false time constraint and get a general conversation going! They'll be happy to talk to you and when your conversation runs dry simply excuse yourself. There's no pressure at all, the time constraint will disarm them and make them feel relaxed so all you need to do is use a simple situational opener or something. After that, you'll find you can go up and talk to anyone. If you have a routine or two stacked and go into your next set you'll surprise yourself with what happens.