Your Outfit
Yes the trip itself will cost you some money, but you definitely want to get some new clothes before your trip. Everyone else is going to have brand new clothes that they bought specifically for Spring Break, and you definitely don't want to look like you're wearing hand-me-downs.
Also, just because you think it looks good, doesn't mean that is true! Take someone of the opposite sex to the mall with you and have them help you pick out some clothes. Make sure whoever you take has good taste, you don't want the blind leading the blind.
Swimsuit shopping should definitely be included since that's what you'll be wearing a lot of the time, so get some new bikini's or board shorts. Don't forget to find clothes for the bar and for dancing at the club. Also, you might want to get some clothes for cooler weather JUST IN CASE. Spring break isn't quite July, so it isn't unheard of to get chilly when the sun goes down.
Hit the Gym
Let's face it, the 9 months since last summer may have not been the greatest for taking care of your body. Spring Break is about partying at the beach, and if you want to look good then you need to put in the work! Even if it is just walking, you should definitely be doing SOME form of exercise for 30 minutes a day starting AT LEAST six weeks before your trip. The sooner the better.
Tanning
You make think you're going to spring break to get a tan, but trust me, you don't want to show up in front of everyone at the beach all pasty white. Yeah it might seem kind of feminine for guys to go indoor tanning, but just do it. You want to look your best when your trip rolls around. Plus, by the time spring break is over, you'll have a real tan to show off.
Shades
You're going to need some sunglasses all day every day at the beach or pool. Make sure to take some time to get some cool, new sunglasses before your trip! You'll look like a wannabe with fake Oakley's, so make sure to get something nice. This is another good time to bring a friend along to tell you what looks good. Bigger isn't always better (girls), it depends on the shape of your face.
You'll also want to make copies of things like your license, passport, and driver's license before you leave. This will save you lots of hassle if you happen to lose them while you're on your trip. If you didn't take this precaution, you won't be able to get into bars/clubs, and you'll be hating life.
Find more info about Spring Break at https://www.inertiatours.com/