Track absolutely everything you spend - can be daunting at first but really helps show you where your excessive spending is. I did it and saw just how much money we were spending on groceries. Switched to shopping weekly online and have nearly halved our food bill!
Always pack your own lunches instead of buying out
Make meals where the leftovers can be turned into something else
Switch your bank account, many will give you money for doing so (but you would need to clear OD first so maybe one for the future!)
Look online for coupons or free samples of things you already use
Don't be brand loyal - choose the fabric softener etc that is on offer every time
Shop around for insurance, utilities, phone contracts. Switching is incredibly easy now.
Shop online - even with the delivery fee you'll save so much money by not being tempted into extras and by seeing all the deals plainly in front of you
Use nectar points to double or quadruple up on meal vouchers for nights out (£5 in nectar points gets you £20 in pizza express!)
Cut food waste by using frozen veggies in things like pasta sauce and chilli - cheaper, easier and just as nutritious as fresh
Check freecycle for any furniture / equipment you're thinking of buying. You would be amazed at what people will just give away.