Some things to avoid if you are actiely Trying to Conceive:
1) Saliva: it can kill your sperm. It is best, not to engage in oral sex before you have intercourse.
2) Some commercial lubricants: many of them will decrease your chances of conceiving. If you must use lubrication, real eggwhites are ideal. Also, a new product, Pre~Seed Intimate Moisturizer, has been receiving rave reviews from women, so it may be worth a try.
3) Woman-on-top position: it should be avoided at time of ejaculation.
4) Getting up immediately after intercourse: if possible, give the sperm some time to travel by lying down afterwards. Some women like to lay on their back with the knees pulled up to the chest.