You should start taking a prenatal vitamin and a folic acid.
Also, ditch the soda and coffee if at all possible and stick to water. Obviously having one every now and then or even one a day won't do any harm. But if you drink a ton of it, definitely cut back!
Pomegranates and avocados are WONDERFUL fertility foods. So are some nuts (not peanuts or cashews but walnuts, almonds, etc.).
Cut back on processed foods and fast foods. All the frozen meals you can buy? Processed! Check out labels when you shop for foods and find the ones with the most natural ingredients. I LOVE Campbell's Healthy Request soups. They're low in calories, they don't contain MSG and they taste great! Plus they have REAL ingredients.
Get plenty of SLEEP. Wouldn't think it'd be a big deal but by not getting enough sleep people deprive themselves. Sleep is SO very important for so many reasons.
Exercise!!! Keep your body fit. If you are overweight it's a great time to try to shed those pounds. We have a GREAT forum here at MedHelp for helpful tips:
http://www.medhelp.org/forums/Weight-Loss--Dieting/show/190?camp=msc