If you live in USA, you may find this post useful:
Websites for the frugal
For all others – the key is in the “little things”. A can of Coke, a pack of cigarettes, a chicken burger, a pack of chocolate – those add up to quite a big sum in the end of the month, believe it or not.
Don’t be mistaken – you may think it’s easy to give them up; but try to actually not doing it instead.
Good luck ! (you’ll need it)