Make sure there's an inventory and take plenty of photos of your house / room when you move in; this shows what was there when you moved in and if anything was already dirty or broken so your landlord / the university can’t blame you later and try to keep your deposit.
If you're renting privately and your landlord doesn't arrange an inventory, you can make your own. Try to get the landlord to sign it along with everyone who lives in the house - if the landlord refuses to sign, get an independent witness to sign instead.
Shelter has more information about inventories.
Make sure you tell the landlord in writing if there is any disrepair so that you won't be blamed for it later.