Water, water, and more water. Keep water with you and drink it at all times. Don’t spend huge wads of money on bottled; drink tap, either straight or filtered. If you hate water, get the flavored carbonated waters from Walmart or Target. They’re especially good for weaning yourself off soda, because they’re sweet and bubbly and some flavors have an acidic tang to them. They have no calories or sodium, and they’re generally cheaper than buying soda. The water serves two purposes; it helps prevent water retention that can make you look bulkier than you are, and it keeps you full so you eat smaller portions.
Keep a bowl of cut-up salad base (I tend towards romaine and red onion) in the fridge all the time, along with cheese and nuts and leftover meat from your dinner. Then you always have a fast, easy, healthy option for meals or snacks, which tends to cut down on the times you say “screw it” and grab some McDonalds or eat a box of Easy Mac for dinner or gobble down a bunch of crap waiting for dinner to cook.
Learn about the things you can do with a whole chicken–you can often buy an entire chicken for the same price as a pound of boneless, skinless breast. Invest a few bucks in a pair of poultry shears, and with a bit of practice you can cut one up in less than five minutes. I’m partial to roast chicken, where you butterfly it, rub it with a bit of mayo, season, pop it in the oven, and forget it for an hour or two. Eat some of it that night, some more for lunch the next day, pull the meat off the bones and make soup or chicken salad or top a green salad. You’ve got several meals for minimal money and work. (Since it’s just you, you might consider cutting chickie in two and freezing half.)
You always, always need some protein in your snacks, or you’re going to be snacking again in half an hour. At home, I really like to top popcorn (airpopped or stove-top, none of that expensive, greasy microwave stuff) with garlic salt, a teensy sprinkling of sugar and cinnamon, and some almond slices. The popcorn gives it bulk without a lot of calories, so it’s more satisfying than just eating a handful of almonds. The almonds add dimension to the flavor, so the initial snacking experience is more satisfying, and the protein keeps me satisfied for several hours. I also like popcorn with just about any sort of cheese sprinkled on. I’m specially fond of cheddar and pepper jack, but mozzerella or parmesan is good too.