My OB's nurse advised me to avoid "Italian, Chinese, and Mexican restaurants" -- bascially avoid simple carbs -- to keep the weight gain to a minimum. The white pasta, white rice, and flour tortillas in those foods are simple carbs (not to mention the cheeses and other yummy things that add calories and fat!).
I cooked at home a lot and used whole wheat pasta and brown or wild rice for complex carbs. Mexican food is my favorite, and I have no willpower when presented with a stack of warm flour tortillas, so I avoided it as much as possible. Anyway, it wasn't as much fun without a margarita or a cold Dos Equis!
Drink a lot of water. It's good for the fluid levels in the womb, and it's also a good way to fill up without calories.
I also walked a lot every day of my pregnancy. My walks got shorter and slower as I went along, but it really helped keep some weight off, and my OB said it would help make the delivery easier, too. I also did a pregnancy yoga DVD a few times a week. It helped stretch out my back and legs. Do whatever kind of workout you can do -- exercise is a good appetite suppressant, and it helps circulate oxygen to the baby.
Good luck, and congratulations on the new baby!