Tuxedo-style jacket in plain black with either peaked lapels or a shawl collar. The lapels can be faced in black satin or left the same surface as the jacket, though the former is more traditional and a bit sharper-looking.
Matching black in the same material as the jacket. There should be a stripe of satin (the same satin that's on the lapels) down the outside of each trouser leg. They should be held up with suspenders, not a belt.
Plain white with a stiff vertical band (called a placket) in the center where the sides join. The buttonholes will be holes on both sides, fastened with studs rather than sewn-on buttons. Cuffs should be French-style.
A plain black bow tie. Take the extra five minutes to learn how to tie one yourself, rather than using a clip-on. It's about as easy as tying your shoes. It'll look much better. People will notice.
You could rent formal pumps to go with the outfit, but if you have a pair of plain black dress shoes of your own I'd recommend shining them up and wearing them instead.
You can wear either a vest or a cummerbund. Either one is fine, but plain black satin is preferable for both. You can wear a colored cummerbund, but if you do, stick to very dark and sober colors.
You can wear either a vest or a cummerbund. Either one is fine, but plain black satin is preferable for both. You can wear a colored cummerbund, but if you do, stick to very dark and sober colors.
Unless your school specifies in explicit terms that you have to wear black tie, you can treat prom as a “black tie optional” event. That means that instead of wearing a tuxedo you can wear a plain, dark suit with a white shirt.
Try not to get talked into matching outfits. A little complementing contrast between you and your date is a good thing. You're trying to look like two charming young people, not a wedding cake topper.