First, you the mother need to prepare your own body. Carrying a child uses a lot of nutrients and energy, and your body works extra hard while pregnant. Your liver, kidneys, and heart process much more toxins, blood, and other fluids than when you are not gravida. If you plan on getting pregnant in the next year or sooner, I recommend including some nourishing herbs in your diet. These include nettle, sea vegetables, and dandelion. Nettle can be eaten as a fresh herb in the spring, cooked into casseroles and pasta dishes (you can find it at farmers markets or growing wild; wear gloves while harvesting and preparing - they don't sting after cooking). You can take it freeze-dried in capsules, or brewed as a tea. Health food stores carry the capsules and the dried herb. It makes a nice iced tea, especially mixed with Raspberry Leaf, another great herb for to-be-expecting or pregnant women.
Sea vegetables like seaweeds and kelp are high in many nutrients, and help your body purge toxins. Eat them in sushi, salads, or soups. I like to munch on dry nori paper - the wrap for sushi - as a snack.
Dandelion root and leaf are high in nutrients and also help support the liver. They can be bitter, so I recommend either a root tincture or a wild-harvested leaf salad with Goddess Dressing (the tahini and garlic balance the bitter greens) and flax seeds. Pick them from a chemical-free yard in early spring, wash well, and toss with dressing. You can also find the greens and the tincture at health food stores, but I find the grocery bought greens rather disappointing.
Men preparing to conceive a baby should eat foods high in zinc, like pumpkin seeds. Like their female partners, they should reduce any consumption of alcohol and quit smoking. Both partners should eat organic foods. Studies show that men who eat organic have higher sperm counts, and that the pesticides in conventionally grown foods can cross the placenta in pregnant women.
When your body is healthy and you feel emotionally ready to welcome in a child, learn to chart your fertility. Fertility awareness is a method of natural family planning that involves paying attention to key body signs, including vaginal mucous and basal body temperature. Every morning when you wake up and before getting out of bed, take your temperature with a basal body thermometer. Record this temperature on a chart. Just before ovulation, your temperature will rise a few degrees. It goes down after ovulation unless you conceive, when it will stay at a higher level than normal.
To check your vaginal mucous, stick two fingers between your labia. Notice the consistency of your mucous; stretchy egg-white-like mucous is fertile mucous, and means you are about to ovulate or just ovulated. Making love during this time increases your chances of conception. (If you are trying to avoid conception, by the way, you should use a barrier method or abstain during this time and four days after the cessation of egg-white mucous). See resources for books on fertility awareness; it is a learned skill that becomes easy after a while and greatly increases your chances of conception.
I believe that conception is a spiritual process, dependant on your readiness and the readiness of your incoming child. It is important to be very clear with yourself and your partner your wishes for conceiving a child, and any reservations you may have. When you both feel ready, make a formal declaration that you wish to become a parent. My husband and I used fertility awareness for six years to avoid conception, and then six months of "aiming" for my fertile period before we said out loud to each other, "I want to be a parent." I got pregnant less than a week after we said this statement. Which is not to say that it is your fault if you cannot conceive, but I suggest doing some soul searching together if your plan is not coming to fruition (literally!).
In short, when you feel ready to become a parent, get your body and your heart and mind ready. Then fasten your seatbelts for the most amazing and crazy ride ever! Good luck!