<<< It's me, hi, I'm the problem it's me!
Hello again, it is the source of the question being asked. Again.
The answer is... People watching. If you are spending time in class and than no time just hanging around on campus you're not gonna observe anything.
Once again, broad advice I've given you has been chipped away and narrowed down to a hyper-specific set of parameters I didn't mean.
Go out, get friends, people watch, talk to people and listen to them. That is how you learn about people if you pay attention. Any kind of person.
If you feel you know people well enough than the character is fine. As I've said time and time again anything I've said it an opinion.