One of the hardest tasks for freshers is to get to grips with the way university differs from school. It can be a shock when teachers start being really pleased if you answer back, and you don't have to hand in your homework for weeks and weeks. You will also discover that since you can now smoke and snog without getting into trouble, university bike sheds tend to be mainly for bikes.
Like anything in life, preparation will help. This means talking to existing students on your course to get a realistic picture of how many rubbish lecturers there will be and how impossible it will be to keep on top of the workload or live on your student loan. Talk to friends and family, too, making sure they feel included in this exciting new step in your life and that they realise how much you will value their support until you meet more interesting people.