I suggest you should be relaxing with ur study for first few days because there may not too much when u first started. make new friends by going to events and society, bar at uni if you are a sociable person. also, if you live in campus , it is the best opportunity to meet new people. in my opinion, having friends around r good for studying and helps u making contacts too, u never know later u need their help for job or sharing a company or anything, so uni is the best environment for this. Make friends early is better because when people already have group of friends for themselves, it may be hard for u to join in, so do it now at the beginning. Some people say they love uni because they are happy, but some people completely hate it, and when i started to ask the reason, quite few of them said because they didn't have closed friends.
For your study, u should expect more advanced thing will come up, and you will realise a-level was so much easier. I dont want to scare you, but you should expect this to come, things will get more harder. Uni always want students to be self-study, know how to research on your own, self discipline, no lecturers will force you to do anything, you do it or u fail, ur choice. If you have homework or projects they may be hard and again, you need group of friends to study with, to discuss will make your life easier and learn from each others. And as the above comment said study regularly is better in the long run, it is true, procrastination is not good, you may write or learn few pages for each lecture so there r so much to catch at exam time. therefore, make sure you know everything, and write them down incase when u revise for exam you will forget what you have done.
so. good luck and I hope my tips help.