Most dieters are used to keeping track of what and how much they're eating -- this is good, but with a few tweaks it could be better. What you eat won't likely directly impact the speed of your metabolism -- it's the total number of calories and your level of physical activity that will speed your weight loss.
To help boost your weight loss potential, choose foods that are high in protein (lean meats, fish, soy), fiber (pick whole grains over refined carbs) and low-fat dairy. Watch your portions and number of calories you eat in one day -- to lose one pound, you need to reduce your calorie intake by 3,500 calories, the amount of calories in one pound of fat. (Losing 500 calories from your diet a day for 7 days will translate into losing one pound in one week).
To figure out what's right for you try calculating your BMR and the Harris Benedict formula to get a good idea of your personal caloric needs. The more you know about how your body works, the better you can work with it.