how can you get into social circles?

If your a lower levell, PQ
I made 9/10 of my buddies in the early stages of MS from pqing. Once you meet one person, they will introduce you to multiple others which will eventually create a circle of "friends" around you.

If your a higher level, sign up for zruns / horntail / cwkpq / etc
As you PQ more and more with these people, you will eventually get closer and closer with them

Also, joining Guilds helps a lot. Most of the tighter knit communities within MS are from people of the same Guild.

Finally
Find out if there is a local vent channel in your server and hang out there. Its a good way to hang out, talk, and get to know others (assuming you have a mic.)

If this is rl
Participate in sports, clubs, activities, or just start talking to people in your classes. As long as your friendly, it really isn't that hard to make friends. If there is one thing i've learned, its that small talk does wonders.

Finally, If your a wrinkly old man that is no longer in school,
Go to Bingo Night.