I'm an introvert, but I've also made a ton (and I really mean a
ton) of friends at varying closeness in the past four years.
Because my introversion is less pronounced online, my first step usually means finding some way to talk to them online. The easiest way to do this is to be in a group with them for some project. It gives you a reason to meet outside of class time, and you additionally have a way to gain their respect and to size them up as well.
I've also learned to have the courage to talk to a random stranger. I just remind myself there's nothing to be afraid of, do it, and stay the course, however it turns out.
Then you talk to them about stuff that's not related to class. It builds up. You suggest doing something; they suggest doing something... whichever. Some more conversation happens, more activities, and suddenly you have to think a little harder to remember exactly how you met this person.
