If you constantly don't have enough money to cover your expenses, you can be overspending, or maybe you need to consider that you are not making enough money. About.com will help you pinpoint what the root of your problem is so you can start to improve your situation.
If you find yourself having to use your credit cards to pay for things towards the end of the month, or if you are just consistently running out of money as the last day of the month nears, your income is probably not keeping up with your expenses.
If you find yourself running out of money at the beginning of the month, then you are almost definitely facing an income crisis. If you can just cover your bills with nothing left over to pay for food, you need to earn more money.
If you find yourself having to make difficult choices about which bills to pay, then you definitely are in a very serious situation. You have to find a solution immediately, which might mean getting a second job or trying to reduce your bills by moving to an apartment that has lower rent or selling your car. Look at both solutions you can enact right away and ones for the future to get back on track.
If you look at your budget and find that there are no extras to cut, then you have a serious income issue. You should never have to choose between paying the electrical bill and buying groceries. If you find yourself having to make those tough decisions, then your income is woefully inadequate.
Also, if you have no extra money for an emergency fund, then you don't make enough money. Constantly worrying about money is another sign that you don't make enough money. Use that worry to fuel your plan for getting back on your feet.
Finally, if you just barely make it each month without reaching your financial goals like getting out of debt or saving for emergencies, then you need to look at ways to make more money.