What happens next?

How to choose your prom dress
Get some inspiration.
Check out different trends that are on the catwalk lately. Look through some magazines to see what you like and dislike about this season's dresses.
You might also look at what celebrities are wearing to red carpet events, and use these things to inspire you but don't fret if you cannot match their looks, these are just for inspiration. Start looking at fashion magazines and stores as early as three to four months before your prom.