Make friends with at least one other guy whose successful with girls. Seriously, if guys who've had no experience with girls were just thrown into a situation where they had to hang out with 4 girls and one other guy for a couple months they WILL learn how to socialize with girls. It's inevitable, if that's what your friend group consists of you will eventually pick up on what to say, when to say it, how to interact, etc.

This happened to me first year of college. I spent most of my time hanging around with all guys, rarely any girls. Then I became friends with my roommate and he was a natural. At times it would be me him and like 5 other girls just hanging out. When we would all eat together I thought man this feels really weird, for once in my life I'm surrounded by all these girls wow. And then after hanging out every day it just became normal, I wouldn't even think about it. We'd all just joke around, laugh and it'd gave me the insight that you don't have to act different from who you are around girls.

Some guys if they haven't been around girls a lot when they're around them they change how they act completely, they stop cracking jokes, stop having fun and start acting all serious and or nice. This is not necessary and you can just say what you want and have fun.

TL;DR, make friends with guys who are naturals. hang out with them A LOT and see how they do it