At 5'7" and 192 lbs, you have a BMI of ~30. A healthy goal weight for you would ideally be 120-160 lbs (a BMI of 18.5-25). So, you would likely be looking to lose ~30 pounds off your current weight. Healthy weight loss is generally less than 1% of your weight per week, or a little less than 2 lbs per week for you. If you lose weight too fast, your body goes into starvation mode--it will actively work against your efforts to lose weight. You will have much better results if you go slow.
BMI is Body Mass Index; it is just a relationship between height and weight. It doesn't factor in things like body composition (muscle vs. fat weight)--obviously, a body builder might have enough muscle to have a high BMI. However, it does give you a rough estimate of the range of healthy weights for your heights.
With weight loss, everything comes down to calories. If you take in more calories than your burn, you gain weight. If you take in less than you burn, you lose weight.
In general, there are approximately 3500 calories in a pound. This means that to lose 1 pound per week, you need take in 500 fewer calories in food than you burn each day. This can be accomplished with a combination of dieting and exercise. The exercise is especially important. When you are losing weight, if you don't use your muscles, your body will steal from them instead of from the fat. It is much easier to burn protein for energy than to burn fat.
A few suggestions:
1) read nutritional labels or look up calorie content on the web. For example, 2 cans of non-diet soda is nearly 500 calories. If you drink soda, this would be a super easy way to cut back on your calories in. I would almost guarrantee that if you check your current diet, there are things you can cut out that you won't miss that would quickly amount to a lot of calories. They hide everywhere, not just in normal "junk" food. Think muffins, anything from a coffee shop (sugar, cream, frappuccino...), sports drinks, etc. Juice is another one--aside from a little Vitamin C, it's just sugar water with as many calories as Coke. Drink water instead and take a vitamin.
2) The best diet is one you can stick with for LIFE. If you can't live without pizza, do not start a diet by cutting it out--you would just be setting yourself up for failure. Your first changes should be the easiest ones you can make so you can stick with them. For example: replacing soda with diet soda or Fruit2O, eating cereal or an egg instead of a muffin at breakfast, replacing your snacks with carrot sticks or fruit, etc. As you lose weight, your motivation and confidence should increase, and you might be able to make harder changes in your diet.
3) Don't buy into fads like low-fat, low-carb, etc. A calorie is a calorie, it doesn't matter what form it comes in. In general, a healthy diet is ~30% fat, 20% protein, 50% carbs. The best fats are monounsaturated, followed by polyunsaturated, saturated, and trans. Any fat from an animal is worse than a vegetable fat. However, this stuff is more important in regards to your heart--your waistline sees them all as the same thing.
4) High-fiber foods like whole grains keep you full longer, so you might eat less. Stay hydrated. Small frequent meals help some people, especially if you are used to "grazing" between meals.
If you want to learn more about nutrition and dieting, your insurance might cover a consulation with a nutritionist. If not, it might still be worth the money. Also, my school has one available for free, so if you are a student, that might be another option.
If you have questions, feel free to ask me. I lost about 20 pounds in high school, and have maintained it for the past 7-8 years. I think the most important thing I learned was that you don't keep weight off by making sacrifices you can't maintain. Whatever you do, it has to be something you will stick with for the rest of your life.
Think about it this way: the way you live your life now is what makes you this size--if you want to change your size, you need to change the way you live your life, too.