what should I do/ expect before I start college?

[irving snotpocket]

It sounds like you already know your weaknesses (writing skills/spelling). Yes, start acting like an adult. Yes, the work load is harder, but different. The biggest three most significant skills to work on?

1) Written communication (yours isn't bad, but you need work)
2) Time management: you will be bombarded with ways to spend your freedom and time, choose wisely
3) Note-taking skills (get a Smart Pen)