The most important word you need to know regarding weight loss is "calories". Your body needs calories to survive and it burns calories all of the time--even when you are asleep. Every time you eat you take in calories, the amount depending on the food consumed. So weight loss is really just a calorie game. If you take in more calories than you burn up you will gain weight as your body converts the excess calories to stored fat. If you burn more calories then you take in then you will lose weight as your body takes the stored fat and converts it to energy to make up for the calorie deficit. It is really just that simple.
The best way to keep track of the number of calories that you are consuming is to read food labels. If you are planning to go to a restaurant, visit the website first. Many restaurants offer dietary information online. You should write down every food you eat and then track the calories. At the end of the day add up the numbers and you have the number of calories that you have consumed. If that is too much trouble, try to find a diet plan that has already done the math for you--and simply follow the plan.
The more active you are the more calories you will burn. Any activity burns calories, but the more strenuous the activity and the longer you do it, the more calories you will burn. Walking burns more calories than sitting and running burns more calories than walking. So just get more active and your burn rate will go up.
Will Cutting Calories Lead to Weight Loss?
If all you do is cut the number of calories you take in without any other change to your lifestyle you will lose weight, assuming you cut calories enough to get below the amount of calories you are burning. You will continue to lose weight until your body adjusts to the new lower amount of calories at which time you will stop losing weight. At that point you will have to cut calories further in order to continue to lose weight. One thing you will notice is that not all weight loss will be fat. Your body will start to shed muscle tissue after a period of time in order to produce energy. The only way to avoid this is to do exercises that increase muscle mass.
You will do much better while cutting calories if you increase your caloric burn rate by exercising. You can, however, continue to lose weight by cutting calories without exercise until you reach the point where you can no longer cut calories any more without compromising your health. You need a certain level of calories each day in order to sustain your body. Once you reach this level you should be at a weight that is optimal for your body.