Basic primer on veg*n eating:
So, every day, on average, a breastfeeding woman needs about 2300 calories a day. You want to make sure that you are eating plenty of fresh vegetables and fruit - the more vividly colored the better, and in a rainbow of hues. You want AT LEAST 5 servings a day, I feel best eating more like 10. Make sure that, at the minimum, you get one dark green leafy and one bright orange in every day, and something with vitamin C, strawberries, bell peppers, citrus.
Whole grains are full of B-vitamins, iron, protein and fiber, I shoot for about 6 servings a day there. Brown rice, whole wheat breads and pastas, quinoa, corn tortillas and polenta.
Legumes, nuts and seeds are what you are essentially replacing meat with. They have lysine-rich protein, iron and other minerals, and plenty of fiber. Black, pinto, navy, kidney, cranberry and cannelini beans, lentils, almonds, peanuts, sesame, sunflower and pumpkin seeds are the ones that I eat the most. 3 servings is what I aim for.
As far as dairy, I don't eat it and don't really try to replace it with substitutes in my daily diet. I do put soymilk on oatmeal and in muesli, and I add it to my coffee, but I don't drink it by the glass most days. I eat lots of green leafy veggies, sesame, and almonds for calcium.
As for fats, you want to make sure that you are getting enough, they boost nutrient absorbtion and help you feel full longer. I don't eat many refined fats, but I do eat avocados, nuts and nut butters, coconut and coconut milk.
You don't need to eat soy foods, though organic tofu, edamame, tempeh, and soy milk are things that I eat in the legume category. Tofu I use more to replace eggs and cheese than meat.
One of the pitfalls that many new vegetarians fall into is replacing the meat in their diet with lots of eggs and milk, especially cheese. Even if you aren't giving these up, replacing meat with them is not going to improve your health. Here's some food ideas to get you started:
Oatmeal with fresh fruit and nuts
Scrambled tofu loaded with fresh veggies - I usually add onions, mushrooms, cabbage, carrots, and kale to mine.
A whole grain bagel or toast spread with nutbutter and topped with bananas
Roasted potatoes and sweet potatoes with onions and garlic powder
"Quesadilla" Whole grain tortilla spread with refried beans topped with salsa and avocado.
Bean or vegetable soup with bread
Hummus with crackers, pita or toast wedges and raw veggies to dip
Big green salad with beans, nuts, dried fruit
Peanut butter and jelly
Veggies and extra firm tofu stir fried with teriyaki sauce and brown rice
Red lentil curry with seasonal veggies cooked with coconut milk served over quinoa
Black bean tacos with cilantro-lime coleslaw and fajita veggies
Pasta E'fagoli (whole wheat pasta with beans and veggies and a spicy red sauce)
Barbecued tempeh with baked potatoes and steamed veggies