Firstly, just a little tip; start looking early.
And when I say early, I mean early. The sooner the better, in fact. I'd encourage you to start looking and asking about accommodation for the following year before Christmas. That way, most of the rooms and houses haven't been taken yet and you have more of a chance to get a better location and room. Once the good ones are gone, they're gone.
Also, don't allow this to scare you into just choosing the first one you find, have a look around and find the best place for you. There could always be something nicer for a better price or something else included in the rent which wasn't in the last.
Remember, you have to live here for at least a year, so make sure it's somewhere you can actually see yourself living. You don't want to be miserable and regret not looking further and sooner.
Choose wisely who your flatmates will be. This is important, you have to live with these people for the next year or two.
For example, I was supposed to be living with some of my flatmates from Halls, but things happen and now i'm moving in with my boyfriend. But I was in a panic for a couple of weeks when I first had to start looking for somewhere by myself, because I hadn't looked beforehand. It was a very stressful time. I wouldn't recommend doing what every student does, and leave it until last minute. Moral of the story: don't rely on plans. Things change, so make sure you have other options. Get it sorted!
Websites such as this are a very useful tool when looking for somewhere to live, they list all available accommodation and tell you exactly what you're getting for how much, which makes looking so much easier!
However, don't panic too much if you leave it late. There are always available rooms, even if you do end up living with someone you don't know. You never know, they could be the best people you ever meet!