The human body burns calories naturally. The amount burned all depends on the amount of activity you normally get. If you work a desk job you will burn fewer calories than if your job involved walking. If you take this number and then factor in your height and weight you will find how many calories you naturally burn in a normal day. Normal meaning without exercise or extra activities. Take that number and you have the amount of calories you can eat to maintain your weight. If you want to lose weight you eat less calories and if you want to gain you eat more. Most people eat more calories then they think and that is way obesity is a growing problem on our planet. A recent study found there are more people in the developing world that are overweight than there are hungry. "Worldwide, more than 1.3 billion people are overweight, whereas only about 800 million are underweight—and these statistics are diverging rapidly." (http://www.scientificamerican.com/article.cfm?id=the-world-is-fat). Eat 1000 less if you want to lose 2 pounds a week 500 less if you want to lose 1 pound a week. To find your caloric intake, visit this site: http://www.freedieting.com/tools/calorie_calculator.htm
Be honest with your weight and exercise level when using this otherwise the numbers will be wrong and you wont lose anything. On another note: you do not want to lose more than 2 pounds a week. What you see on the Biggest Loser is not representing of what a successful weight lose program is lost. They are being constantly supervised by doctors, nutritionists and personal trainers. Unless you have 2000 dollars a week to spare you will not have that kind of supervision. It is up to you to track what you are doing and hold yourself accountable for a safe and steady weight loss. IF IT HAS BEEN A MONTH AND YOU HAVE LOST ONLY 4 OR 6 POUNDS YOU ARE DOING GREAT! I cannot stress this any more: don't be down on yourself because you have only lost a few pounds in a couple weeks. When you are down on yourself, you will go back to the way you were and you will gain 10 pounds in 2 weeks. You don't want that. Be proud of what you accomplish; no matter how small.
There are many ways to keep track of your calories. You can use pen and paper or you can use a site like loseit.com or myfitnesspal.com. I use loseit.com and, using their android or iPhone/iPod app I can see right away what I have consumed for the day and know what I have left, no matter where I am. Myfitnesspal also has an app that is also very good. If you don't have a smart phone keep a pen and paper with you and record as you go. If you don't know the amount of calories then write down what it is and look it up later. Once you get home at the end of the day, grab your notepad and record it all down on Loseit or Myfitnesspal. Over time it will become easier to guess how many calories are in an item.
To get an idea of what your normal caloric intake is before you start to count eat what you do normally. Don't lie to yourself no matte how bad it may be. Record it all down on paper don't count any calories, when the night is over add it all up and you will see how bad it normally is. Then you can look and see what you did wrong that day and see where you can improve. I did this and found I had consumed 4600 calories on a Saturday and then 5200 calories on a Sunday. Given that one pound weighs 3,500 calories and I consumed 9800 Calories over 2 days minus that my body naturally burns 6000 Calories over 2 days, I gained over 1 pound in 2 days. Now factor that I probably ate that much over the entire week, 5000 a day times 7 days is 35000 calories over the entire week, my body burned 21000, subtract that from 35000 and I ate 14000 extra calories. That would be a 4 pound gain in a week. Of course the science behind this isn't exact but you get the picture. Count your calories; it really is important.