Lots of beer...
I was always the wallflower. As shy as anyone you could find. It took me 25 years to get to a point of being able to meet strangers and I still get very nervous when I do it.
The only thing I can suggest is being around crowds of people as much as you can, especially with any friends you have that are outgoing. They will always introduce you to other people which gives you the perfect opportunity to try to make small talk. Just a thought. It never worked for me, though. LOL
Seriously, it's rough being shy. I know. I still have trouble with but, I can talk to someone if I want to badly enough. However, I could never be in sales. lol