Its sweet that you have long hair. This way you can do crazy things to it. I'd suggest creating some loose curls just at the end and giving them a bouncing look. You can try doing a fishtail braid - that's looser at the top and then tighter as you continue toward the end. You can try a loose bun. That'll look great. If I tried explaining on how to do these hairstyle. It'll take FOREVER! Maybe you can try google. Or seventeen. Com. They have the steps for the loose bun and lots of other hairstyles. Give it a shot.
You have some choices. If you are ok with heels then I would try black, white, silver or gold stilettos or peep toe heels. Since its navy/purple any other those colors will work. Make sure that if you choose black white or silver shoes then make sure you use silver or diamond jewelry for a nice accent. If you choose gold choose then gold jewelry.
As for the hair are you doing it yourself or going somewhere to have it done? You can completely straighten it and flip curl it or curl it under, or you can do loose pretty waterfall curls. Use some clips or matching headband or something to make sure the hair is pulled off your face.