You should be able to document your income, expenses, and (hopefully) savings every month. If your income minus expenses is a positive number, you can relax a little. You still may want to work on your budget so you can save more for an emergency or retirement. If that number comes out negative, you could be in big trouble. Spending more money than you make means you must rely on credit. In turn, this means you are setting yourself up for more trouble because those credit card payments will get higher every month.
I'm a fan of MS Excel _ my apologies for those who have issues with Microsoft _ because I find its powerful calculations are easy to manipulate to help me better understand my finances. It doesn't really matter though which spreadsheeting package you use so long as you are able to calculate your amounts effectively. There are commercial budgeting worksheets available but if you want to create your own its a simple process.