Oftentimes, this is easier said than done! To budget well, you really need to come up with a reason that's bigger than the impetus you have for overspending. Once you have that reason, you can turn it into a positive motivation to set some new financial goals, such as getting debt free.
In Australia, there is a company called Debt Rescue that has launched a special new programme called Debtstroyer. This program helps people who have difficulty sticking to a budget, need to find regular amounts to pay their bills, want to learn how to save, and need help working out what their weekly and monthly costs are.
Talk to an Aussie Who Cares™ and contact Debt Rescue for more information about budgeting. Here is a link to a great article about debt.