The parties I throw are for college students or recently graduated people. SO:
Get an apartment or a house where the parents won't be home, or don't give a shit.
Get a 30 rack of cheap beer (I prefer Coors Light. PBR, Bud, Miller are all good options.) Get some cheap and kinda nasty alcohol. (Smirnoff, cheap rum, maybe whiskey, etc.) Tell everyone that BYOB is encouraged, but not required, since there'll be cheap beer and cheap alcohol. Most people have standards that are a tiny bit higher than that, and they'll bring something, which is good to help variety.
So, when you're inviting people you should give personal invites. I've tried just blasting out messages on facebook, people often get less excited by those. It's better to personally private-message, email, text or phone-call the people you want to come. If you're organizing a party for someone else, you can still call all their friends.
If you have messy roommates, make sure they clean up their shit before the party. Make sure you have paper towels, normal towels, plastic cups and a clean bathroom. This would also be a good time to put in fresh bong water. Hide all your valuables/breakables. (I had a friend lose two bongs at a party. I almost lost a grinder, but the would-be thief was wise and "pretended to find it".)
And uh, yeah. That's all. Invite the closer friends over an hour or two before to pre-game, that way you already have a core of drunk/buzzed people at the beginning of the party, which really helps everything flow.
Have a deck of cards around, to play King's cup or other stuff. If you can get a beruit table going (just a piece of plywood at table-level) that'd be good too. Make sure you know what your house rules are, because people have a lot of different rules.
And finally, appointment "commanders". I was the co-commander of my parties, along with my roommate Mike. That way if one of us passed out or puking or on the phone, there is still another person to deal with anything that arises.
If the cops had ever come to one of my parties, I would have told Mike to get all the underage people into one bedroom, make sure there's not booze in that room, and then also make sure that everyone else is quiet. Because he would need to do that while I talked with cops. (Remember, you don't have to talk to cops, and they can't come into the house/apartment without a warrant. The best thing to do is to come out of the house and close the door behind you, and talk outside, that way the cops don't construe the open door as an invitation to come in, and they don't eye around.)
Line dances have also been a good thing, for oh about three centuries, anyway. There's not much difference between some boot-slidin' country-western line dances, the Virginia Reel or The Stroll, they all allow groups of strangers to join in a simple ritual that brings them together and makes the rest of the night go better. 
No, if this is for a friend, it demands the ultimate sacrifice: interpersonal communication. 
It was indeed a lot of fun for everyone, and it was surprising how the common goal of just having fun brought together a lot of strangers.
