I have all sorts of habits like that. I bite my nails, twirl or braid my hair, tap my feet, drum on my desk. Half the time I don't even know when I do it. I don't think you will be able to get rid of all your habits, but it's possible you could change from unhealthy ones to harmless ones. Chew gum to get rid of nail biting(I know you can't always do that with school though, sorry) and whenever you start pulling your hair, stop and do something else with your hands. I have a bracelet that I made out of floral wire that I almost always wear that I play with it I need something to do instead of biting my nails. Try to transfer your habits to something harmless. Hope this helps!
I often sit on my left hand to prevent myself from scratching my face or plucking my lips. Perhaps it could help against the hair-pulling. As for the nail-biting, have you tried chewing gum to keep your mouth occupied?
Compulsive hair-pulling/tugging is called trichotillomania. It's pretty poorly understood in the medical community, but it's commonly associated with depression and stress. So this is something you should definitely let your counselor know you're experiencing, if you haven't already. S/he may be able to provide some sort of cognitive therapy routine. In the meantime, this site may prove useful to you: [link]
I started pulling out my eyebrows and eyelashes in late middle school, and it's only been very recently that I've gotten it under control (I'm now 23 years old). The best I can tell you is to redirect your attention when you notice yourself doing it or begin feeling the urge. For me, I found that doing piano exercises on my legs or other finger games helped. Even just plucking at the fabric of my jeans helped to a certain extent.
Keeping your fingers busy may not necessarily ease the urge to pluck, but it will force you to be more aware. Don't get discouraged about relapses, just keep working toward breaking the habit by pushing your urge times. One hour without plucking eventually turns into a half-day, etc. Little victories.