We would advise you organise your finances before fresher's week. This may seem like the least exciting task in preparing for university, but it's the most important.
You'll firstly need to set up a student bank account. Many of the major banks offer these with added attractive incentives such as free NUS Extra or 16-25 railcards, but what you're ideally looking for is who offers the best overdraft facilities. Some banks will make daily charges if you enter your overdraft, so be wary of these and always read the small print.
Once you know how much funding you're entitled to on top of any family allowances and part-time job earnings, you can budget your day-to-day life accordingly. We would advise making a budget, this may seem like a very boring task, however if you make allowances for rent and amenities ( food, phone bill, books) as well as luxuries ( clothes, socialising etc) this will allow you to spread your money evenly between your loan payments so that you can enjoy yourself throughout the year.
It can also be a good idea to have two separate bank accounts, one which your loan is paid in to, and a second which you use to go shopping with.