Here's a better idea: pay attention to what your friends say and use that. There's no point in using certain slang expressions if the listener doesn't also use them. For example, when learners say "wassup" to me, I just start laughing. I know it means "what's up/what's news", but I simply don't use it, and neither do the people from my area. So, no offense to the people who do use it, but it just seems silly for me to use it. Using the wrong slang can be a huge step backwards. So like I said, listen to what your friends actually use.

I'm not that familiar with slang, but here's one I know: Milk it: to get as much out of something that you can (it also has another meaning that I would rather not say....)

Do you have any preferences? Where will you be using the slang? That would make it easier to compile a list for you.