I found this on a web site, I'm not sure if it's 100%, but I thought Id pass it along
Do limit movement after intercourse. Standing up after intercourse can cause the semen to leak out. Try to wait twenty minutes after sex before getting up and moving around.
Do try to keep the sperm inside your vagina longer. You can hold the labia together to try to keep the sperm inside of you. You can also try putting a pillow under your pelvis to help tilt your body so the sperm can travel upwards easier.
Do try to make sex enjoyable. Sometimes when a couple is trying to conceive it will affect the quality of their sex life. More enjoyable sex means higher sperm count and better "swimmers".
Do limit male masturbation prior to the days you are trying to conceive. It will help to increase the man's sperm count and improve your chances of getting pregnant.
Do take prenatal vitamins if you are trying to conceive. Folic acid and other vitamins are very important during the first trimester of pregnancy.
Don't drink alcohol or use drugs at the time of conception. This applies to both the male and female. There is strong evidence that alcohol can effect your chances of getting pregnant.
Don't douche after having intercourse. It can wash out the sperm that has just entered your body.
Don't have oral sex prior to intercourse. There is some evidence that the bacteria in the mouth can cause damage to male sperm.
Don't have anal sex prior to intercourse. Bacteria in the anas can be carried into the vagina from the man's penis. If you do have anal sex before intercourse, make sure your partner washes his penis first.