Oh boy where to start.
1. Do not move out if you are already in debt!!!
2. Do not move in with your best friend, or someone you cannot communicate well with, it can have disasterous effects.
3. As others have said, don't get an expensive internet/phone/tv package. You do not need it!
4. Learn how to cook simple meals such as omelettes (you might call them tortillas), pasta dishes, jacket potatos, stir fries, curries and perhaps a roast dinner or two - for impressing people (ask your mum she should be able to help).
5. Do not move in with anyone that you love or care for, you will end up hating them.
6. Independance can be a little disapointing after a few weeks of staying up to 4am (just because you can), sometimes its very lonely. Keep your friends close and don't be afraid to invite your parents round from time to time. This has added bonuses of your mum cleaning and cooking for you and your dad slipping you extra cash.
7. Last but not least, invest in a good saucepan, frying pan, plate, scales, knife and fork and cooking utensils. Practice cooking especially basics like rice and potatos before you go. Jacket Potatos are good comfort food.
I nearly forgot. Takeaways are extremely expensive and they soon add up. Laziness with cooking results in laziness in other areas of your life. Cooking is a good stress reliever. Also take books and torches for when your electricity runs out. Also don't forget to change your sheets. Have at least 2 of everything so you can wash one lot of bedding while you use the other. I may remember more later...