I think I pretty much agree with what everyone has said. My personal spin:
Exercise DAILY - Doesn’t have to be a lot. Should NOT be a lot at first, especially. But do it at least 5 days a week. I don’t even think it needs to be strenuous, or for a long time. Ride your bike three miles a day, five days a week, and you’ll be astonished at the results after two months. I was never in better shape then when I rode my bike to work every day. It wasn’t far, about three miles each way, but it was exercise every morning and every evening. Amazing what even a little will do, on that schedule.
Drink enough water - Don’t dehydrate yourself. Your body will tell you when you’re thirsty. Listen to it. Bring water along, or have water nearby, when you exercise.
Don’t stop eating! I’ve generally found that the food thing takes care of itself. I don’t believe in trying to diet per se. Do try and eat healthy food. If you eat McDonalds every day, you’re going to have a heart attack no matter how skinny you are or how much exercise you get. Eat salad (throw in tomatos, avacados and carrots to make it less boring, and get good spicy dressing), fresh fruit (bananas, oranges, apples) and pasta (all kinds - I like mine with parmesan and olive oil). I wouldn’t recommend excessive meat consumption, but meat is an excellent source of protein - don’t forgo it entirely.
In general I find that exercising regularly actually has the effect of making me less hungry than sitting around all day. I have no idea why this is, but it seems to be true. So you get a double-whammy by exercising; you’re burning more and eating less.
Point is, don’t starve yourself. If you do that, you’ll lose muscle as your body cannibalizes itself. And you may not lose fat, since your body is frightened that you’re in a famine period and it needs to hoard fat so you won’t die.
Keep doing it forever (literally). Lastly, make the exercise a permanant part of your routine. You may do it for a month and lose a few pounds, but they will come back fast if you don’t keep exercising. This is the hardest part in my experience. Exercising takes time, and if you do it regularly it can take a LOT of time. I find even one hour five times a week really eats into my free time. It’s easy to let it slip. And if you do, don’t feel guilty - happens to everyone. Just get back on the horse and start again.
-Ben