I think the best advice is, pretend you are already pregnant! Take a prenatal vitamin, eat a wide variety of whole, organic foods (easy this time of year, with all those gorgeous fruits and veggies overflowing the bins in the produce section of the grocery), excercise moderately, drink plenty of water, and get your rest. I don't think you need to do anything drastic if you're already eating well and in good health (and it definitely sounds like you are).
We're just about to start TTCing, too, and I'm trying something new this time. I get incredibly sick during early pregnancy, and even if you don't get MS, almost everyone is exhausted in the early months. So at least 4 nights a week, I cook double for dinner. We have the luxury of a deep freeze that makes this easy, but it could work with a regular freezer on a smaller scale. I freeze those meals in individual serving sizes and this will save us from having to eat DH's cooking when I am just too sick to cook.
I'll do it again in the third tri, so we'll have plenty of good home-cooked food to eat after the new baby comes.
And as the PP said, definitely pick up a copy of TCOYF. If you chart your cycles between now and when you start TTCing, you'll be three steps ahead already.
Good luck! Every pregnancy/birth/baby is extraordinary, but there's something so special about the first experience. Enjoy!