To make this work you need to lay down the law. Make sure you and everyone you’re living with knows how things are going to work.
Tip: Call someone out on something quickly. Otherwise you’ll surely be engaged in middle school esque prank battles.

Money: How do you plan on splitting rent? If you’re jointly purchasing appliances who takes it when you move out? What happens if one of the persons involved is a jerk and “forgets” to pay the other person back?
Visitors: When is it a good time to have people over? Is there a limit to how many people you can have over? Who pays for the damage dealt your food supply?
Food & Common Items: Do you share food? If so, how is it paid for? Who pays for things when they run out?
Pets: Is your roommate allergic to any animals? What type of animal is acceptable?
Note: check with your landlord about pets first.

2Friends – In my opinion friends are generally some of the worst people to move in with. By signing a lease with your friends you put your friendship with those people on the line. How well do you really know them? If tiny things piss off when you’re not living together. You’ll want to punch them in the face after like two weeks if you were.

2Complete Strangers – Easily the scariest option of the bunch. If you choose this route sign up with a site like roommates.com. They provide background checks for every single person listed on the site. Honestly this could go one of two ways: It could be an awesome choice, or a real kick in the balls. If you believe people are generally nice until proven otherwise this is definitely something you should consider.

3Boyfriend or Girlfriend – For the most part this is the worst thing you could possibly do. Sure, you may love them now, but who knows what could happen over the period of your lease. Say Lindsey cheats on you 1 month into your 9 month lease. You have two options go back to your parents house, or listen to that jerk Dan plow the women you once loved every single night. Like a 5 year rifling threw their Easter basket for the first time.

4Opposite Sex – Sounds like a dream to most guys, but after further analysis it’d be less than sweet. But seriously, treat the situation like any roommate situation. How well do you know them? Do you get along? The basic questions still apply. If you choose this route be prepared for all your friends/family/acquaintances to get the wrong idea.