i have a perverted sense of love for the man who does this website:
www.moneysavingexpert.com
although its probably only good for UK people.
but basically:
don't smoke
drink spirits on a night out if you have to get tipsy. have soft drinks in between drinks and it'll cost way less.
only shop in sales
if you really love to shop...don't pay for everything on your card. if you actually hand over hard cash it really hits you how much you're spending.
don't buy take out coffees or pre-packed lunches...take 10 minutes to make your own. honestly i didn't realise i was spending £15 a week on fricken sandwiches and hot chocolate. gross.
get friends to copy cds for you
don't buy magazines. £2 a week doesn't seem much, but it all adds up.