Just found this website. It has some good tips: http://www.helpguide.org/life/healthy_eating_diet.htm . And I'm sure you can find all the information you could ever need about eating healthy on the internet.
But yes, breakfast is an important part of jump starting your metabolism. Just eating regularly is important. I heard someone suggest you should eat 4 times a day, every 4 hours. Now, that's not to say you should eat 4 MEALS a day. Eat a smart breakfast lunch and dinner and two snacks like fruit or yogurt.
As everyone knows, soda is very bad for you. You say you're drinking a lot of water, which is great. Another alternative is tea. Crystal Light also makes some great powders you just mix with water. If you can always do water, great. But sometimes I need some flavor in my drink.
Hard boiled eggs have been great for me in the morning. I boil up a dozen on Sunday night and I just grab a couple each morning throughout the week. Sprinkle some salt and pepper on them and they are a quick, easy breakfast on the go. Add a banana or an orange and some steel cut oatmeal and you got yourself a great breakfast.
Beyond that, just eat smart. Eat whole grains as opposed to processed flour. Avoid sugar. Replenish your body with water and fruit as opposed to energy drinks. Eat plenty of vegetables. Portion size is important to keep in mind, but it's not about JUST eating less calories.
Working out in the morning instead of later in the day is also a good idea because working out speeds up your metabolism and releases energy for you throughout the day.
If you can't run by your house or at school, you could find a city park, trails or drive out to a country road. Even if all you have is a back yard you can do sprints from one side to the other. If you have a second floor or a basement in your house running stairs is great. If you have a lake in your town go swim for a while on a hot day. Sure, running in place will burn calories, but I'll bet you can find some kind of cardio to do if you thought about it hard enough.
The good news is you are young. If you really want to join the Marine Corps you have plenty of time to get in shape before you're too old.