If you are taking a multivitamin make sure it is whole foods based. I recommend this one http://www.amazon.com/Garden-Life-Raw-Prenatal-capsules/dp/B002JOVOVY/ref=sr_1_1?ie=UTF8&qid=1319689998&sr=8-1 (the price does go down, buy a few when they are $24.95 if you can). A whole foods based supp is much more easily absorbed by the body than a synthetic vitamin is, and most vitamins out there are synthetic unless otherwise stated.
When you eat iron rich foods such as spinach and other dark leafy greens, beans, nuts, and meat, eat some orange, a kiwi, strawberries, bell pepper, etc with it, any food that is high in vitamin C basically, because it helps you absorb iron as well. Make sure you stick to organic produce and meats. Organic produce is more nutrient dense than is the non-organic, so it will have more iron and vitamin C in it. It also has not been irradiated which destroys many beneficial nutrients including vitamin C. And remember, store bought orange juice does not actually contain vitamin C, because it is pasturized which destroys the vitamin C in it.