Cheapest and most easily manageable ways are to (one by one) subtract sweets, excess carbs and fast foods from your diet, especially gimmees like sugared soda, chips and cookies. Just being mindful of how much sugar, or how many carbs, are in something you often eat, versus substitutes you also like but that are better for you, can make a difference.
Another thing to try is to add or change a daily or weekly activity with an eye to increasing your amount of movement. I volunteer at a local school two days a week, and one of the reasons I like it is because it keeps me on my feet and moving a lot versus sitting at my desk. I find it a lot easier to exercise by making a change that I like that also just happens to involve more movement, than to try to exercise in isolation.
Talk to your doctor and see if he or she knows a good nutritionist, and go see that person, and talk about what you eat and how you eat. It can help if you can find a good professional.
Not sure this is the best way to lose weight. Don't know when your next birthday is, but 30 pounds is a fair amount of weight to lose. Not only are you putting a lot of pressure on yourself, losing weight quickly usually leads to putting it back on again because it require radical steps. What might work better is to not set a time limit and make the changes everyone knows lead to weight loss, which is to basically eat less and exercise, or move, more. As to cutting carbs, this isn't really a proven way to lose weight permanently. Carbs are most of a healthy diet, as they include grains, veggies, fruits, and a lot of what's in relatively healthy high protein foods like nuts and legumes, which still also contain carbs. Obviously, sugar is a problem, as is animal fat other than from fish. But if you don't rush, you don't have to go all austerity about it and can establish a new permanent diet that works for you and that makes you happy. Right now high protein diets are a raging fad, but long-term research on real people doesn't show high protein diets being all that great for long-term weight control. Do some homework, set realistic goals, but it's still the same time-worn story, eat less but eat healthfully and burn off more.
Hello... it's good that you're trying to get healthier. I think the first question is if you really need to lose 30 pounds or if losing fewer pounds would be just as healthy for you. Sometimes we pick a weight that we want to be at, but isn't necessarily where we "should" be.
Skipping meals is usually not a good thing since you're young and your body isn't fully developed yet. Typically, it's recommended that you eat several smaller meals/day.
It's good that you're keeping a log of what you're eating. That can help make us more mindful of what and how much we're actually eating.
Often, as Annie said, just cutting out sweets, chips, soda and other snacks as well as cutting down on things like bread, potatoes, rice, pasta, etc can go a long way toward helping us lose weight.
You have over a year to lose the 30 pounds, so you should be able to do that in a reasonable manner, just by making small changes to your diet.
Good luck and please keep us posted on your progress.