(For example, loud parties; friends visiting late at night; want them to move out; will not help with household chores.)
The old saying that an ounce of prevention is worth a pound of cure definitely holds true here. In other words, know as much about your roommates as possible before you rent an apartment with them. Talk over how and when bills will be paid, everyone´s study/class schedules, when it is appropriate to invite friends over and when it is not, private space for each roommate, cooking and kitchen responsibilities, and more. Put these items in your roommate agreement.
Sometimes, no matter what you do, you will still find a conflict with a roommate. First, try to talk with the roommate to work things out. Put suggestions in writing and have everyone sign it if it helps. If talking among yourselves does not work, try getting professionals involved. Call The Mediation Center (TMC) at 441-5740. Trained mediators can help you work things out.
If you cannot resolve your differences by talking or mediating, then you might need to consider either you or the roommate moving to another place. Just remember that you have responsibilities to the landlord if you break the lease.