Prepare the room for future parties (the club, leased a country house, restaurant). For this you may need a lot of things: balloons, garlands, posters, and more in line with entertainment. Check the sound and lights, and prepare for the dances, buy the CDs with the desired music, if you are going to invite a master of ceremonies or DJ.
Make a guest list. Importantly, it was not implacable enemies, otherwise the party could turn into a massacre. Apologize to one of the parties, which on the occasion to invite not to be, as if you wanted to. The list should contain roughly the same number of women and men, so nobody felt deprived.
Decide whether to arrange only a disco, or you can enjoy a varied entertainment programme. Do not let them get bored: let one number replaced by another every 20 minutes, during which you can dance or eat and drink.
You might want to arrange a stylized party. For example, in the style of Latinos, vamp, or "a La Rococo". All of this will require a certain drawing, music, menu. Not sure in this case, pre-warn guests that they have the appropriate costumes. If you wish to surprise them with your stylized party, don't tell them anything, and better prepare the sets of any era, country, etc. They will be handing out at the entrance to prepared for the arrival of guests room. However, the owner better be in full uniform.
If you decide to arrange a home party, you will have to be limited to a small number of guests (depending, of course, matter what size your home or apartment). And accessories for a party you will be able to use any items of the interior, beating them, for example, as the furniture of the castle, or decorate with flowers to make the guests of the Association with the distant southern countries.