Like the unbudget idea from Baraka above, keep a diary or collect the receipts of your spending every day, then at the end of the month have a look through, add up your spending on necessities, semi-necessities and complete waste. Don't kid yourself as to what ounts and doesn't, it all counts.
Set yourself treats equal to about half the value of what you an cut out, over increasing periods. Week, fortnight, month, quarter, half-year, year.
You'll be amazed how much you waste on aggregate, probably, and from that a drive to budget can be forged.
(it works for weight-loss as well, or did for me, i could see the aggregate effect of all those innocent treats in black and white... sobering.)