The first step is asking someone special to attend the venue with you. It is expected for the boys to invite the girls but either way would work so long as someone asks you. There are always those who have a hard time finding someone and go alone but traditionally everyone has a date.
The next thing to sort is the clothing especially if you're female, the boys usually start with renting a tuxedo which can be a disaster so take your date cause she cares what you look like. It is not always best to go shopping for your outfit with your friend as prom night can get quite competitive. Buying a corsage is another tradition just ensure it will complement your girls outfit, or there will be hell to pay. Girls if you are unsure your date would be able to pick a decent corsage go buy a back up one to save the disappointment, men!
To make the night really special for your date hire yourself achauffer driven limousine for the special occasion, most people will share the cost between a few couples so it can work out very good value and give you an amazing experience to start your adult life in style.