What most naturally follows?

How to concentrate at university level classes
Avoid talking to strangers during lectures and tutorials.
While it might be nice meeting new people and discovering their interests, there are better times for doing this than during teaching sessions when you need to be concentrating.
Avoid talking to your friends.
They're your friends and they'll still be there after the lecture/class/tutorial. In fact, they might start getting on your nerves if they're around too much over-analyzing all the work in front of all of you.