1. You need to eat. There's no need to go crazy counting calories just stick to appropriate serving sizes and you'll be on your way. If you really want a benchmark, aim for 1,800 to 2,000 calories daily if you don't exercise, and up to 2,400 if you do. If you're breastfeeding exclusively, you can add another 500 calories to your daily intake.
2. Focus on your hunger cues. Pay attention to how you feel: On a scale of one to ten, if one is "haven't-eaten-in-days starving" and ten is "stuffed like a Thanksgiving turkey," aim to be around a four when you start a meal and a six when you finish.
3. Watch the clock. Eat something about every three or four hours to keep your blood-sugar and energy levels steady throughout the day.
4. Go slow. Plan to lose only one or two pounds a week, especially if you're breastfeeding. Losing weight too quickly can impact your milk supply.
Here's a simple, low-effort way to get the nutrients you need:
"At every meal, make sure to include three food groups. For every snack, include two food groups." Eat these foods every day:
(at least 3 servings) One serving equals 1 medium whole fruit or 1/2 cup (a generous handful) of cut-up fruit (or juice)
(at least 4 servings) One serving equals 1 cup leafy greens or 1/2 cup (a generous handful) of cut-up raw or cooked veggies
(at least 3 servings) One serving equals 1 cup milk or yogurt or 1 1/2 ounces cheese (about the size of your thumb)
(at least 4 servings) One serving equals 1 slice bread or 1/3 cup grains (a palm-size handful)
(at least 3 servings) One serving equals 1 ounce of nuts (a small handful), 2 tablespoons peanut butter (golf-ball size), a 4-ounce (palm-size) portion of meat or fish, or 1/2 cup beans (a generous handful)
(1 serving of a favorite food every two or three days) Check nutrition labels for serving sizes
adapted from: http://www.parenting.com/article/the-hungry-new-moms-diet-plan