A good way to map out your spending habits is to create a spending and saving plan.
A spending and saving plan is simply a "map" of all the money you receive and spend over a period of time.
Making a spending and saving plan is easy. Try starting out with a weekly spending plan for next month. Start by estimating how much money you'll receive each week, and from what sources.
For example, you might get money from an allowance, a job, for a holiday, or for your birthday. Write this information down for each week. You can also try keeping a money diary.
Next, think about what you're going to spend money on during the next month. Make sure to try and remember everything: snacks, CDs, clothes, etc. If you're not sure exactly how much something costs, make a guess.
Now, see if your spending and saving plan works, that is, make sure you have more money coming in than going out. You'll probably want to leave a little extra spending money in your plan, either for saving or in case something unexpected comes up.