This may seem like a no-brainer, but greens are definitely the way to go. Between cabbage, kale, and spinach, it's easy to find a salad base that suits your tastes (and all three are packed with vital nutrients for barely any caloric cost)--and that's not to mention Romaine, arugula, and butter lettuce. Plus, there's broccoli, peas, and Brussels sprouts, and no excuses not to eat your veggies when they can be prepared so many delightful ways.
Skip the bacon-and-eggs breakfast and sip on fresh juice or a healthy smoothie instead to cut down on fat and boost your energy. And no, a smoothie from the local strip-mall chain probably doesn't qualify as healthy (many are packed with added sugars). Instead, make your own smoothies at home from fresh fruit and plant milks, or if you're lucky enough to have a juicer, start your day with a nutrient-packed green juice.
A good rule of thumb when trying to shed unwanted weight is to start your day with a spoon and end with a spoon (in other words, try a low-sugar or sugar-free oatmeal or cereal recipe for breakfast and a veggie-packed soup for dinner). From Healthy Baked Oatmeal to Middle Eastern Split Pea Soup, you'll be eating so well you'll forget you're on a resolution.
Low-fat, low-cal, low-carb. Beware when these words appear on the labels of processed foods, but don't be afraid to do some home cookin' with these principles in mind. Being mindful of unnecessary fats, calories, and sugars doesn't have to hurt the flavor and quality of your food, and can actually steer you towards healthier eating habits in the future.