I don't keep track of my weight. It's a family rule that there are no scales in the house. I get my weight taken twice a year. Once at my annual doctor's physical and once for the start of school athletics (I don't know why they do that, but they do).
Over the past year, I lost 2 inches from my waistline, but gained 10 pounds. I took off my fat and put muscle in it's place. Remember that, muscle weighs more than fat does, so even if you weigh a lot, it may not be fat.
Right now I'm putting myself through a torture session three times a week for an hour and a half with the school athletic trainer. We do cardio, agility, weights, everything. I'm sore right now, but that means that what we're doing is working. It's a build up of lactic acid. That's a good thing, means that your body's working overtime. Don't be afraid of the pain after an exercise, it's a good thing. Unless it's excessive. If you can't bear to move, something's up.
I have cut out soda (except for the occasional glass with lunch at a restaurant), I started eating more salads and fruit and less chips and popcorn. Fruit Leather is amazing stuff and so are Luna Bars. You should check them out.
I can't run due to bad genetics (I have plantar faciitis. It's not pretty). Running is super painful, so I bike for 20-30 minutes instead. Don't work out every single day, or if you do, do a different body part. If you keep working the same part of your body you won't give it time to heal and recover and you'll start going backwards instead of forwards. Do your legs one day, your core (abs and obliques) the next, take a break on the third day, on the fourth do your arms, and on the fifth day do a cardio work out, then take a two day break (works best when those two days are the weekend, because then you're free to hang with your friends) and repeat the cycle. This works amazingly well. Make sure to warm up well before exercising. Stretch each body part (regardless of whether it's the one you're working on that day or not) for at least 30 seconds to get a good stretch out of it.
You don't need a lot of equipment, either. An exercise ball, a chair, and a set of 5 or 10 pound hand weights is all you really need. You can do crunches on a mat or even just on your floor- push ups, too. The exercise ball also works well for crunches, pro presses (weight workout), and for walk-outs (an upper body workout). A chair works for step-ups (your legs) and for weights. It's super simple.
Sorry for the super long post!