I second TopCashback!If you buy online definitely join that. Getting other people to join it gets you extra money as well.
Buy non-perishable foodstuffs in bulk. A family size double concentrated bottle of squash will last a long time and work out much cheaper than paying £1 or more for some from the local shop.
Lentils!I know they're stereotypically student food, but if you cook them right-they're nice!Ace for making curries,chillis, dips, soup, and they're very cheap especially if you buy yourself a huge bag.They cook quickly and don't need any pre-soaking.
Quit the gym membership and run outside. It often burns more calories than running on a treadmill and it's free.
Walk instead of taking the bus-it incorporates exercise into your daily routine as well as saving money.
If you buy booze , find someone who deals in it and buy off them. EG I know a guy who gets vodka bottles but only sells in 6 packs. It works out about £6 a bottle as opposed to cheapest I've found it in shops is £9.He sells wine too , works out about £2.50 a bottle. There will be someone near you who does this.
Ditch the expensive skin care products. I use castor oil, coconut oil,soybean oil. To moisturise and to remove make up-even regular vegetable oil works to remove eye make up, it's a bit greasy but every trace is gone easily and then use a babywipe to get the smudges off.
All I can think of for now!