Depends... This really depends on age, but in general use an ovulation detection kit and timed intercourse.
Should be easy at 19. Avoid excess alcohol, smoking, marijuana, other drugs, and review prescription meds with your doctors. Aim for normal weight if you're overweight. Take a prenatal vitamin. Have intercourse 2-3 x a week and see a rei specialist if not pregnant in a year, or sooner if you have irregular cycles. If you have regular cycles you can use an ovulation predictor kit and time intercourse around ovulation.
Time. Most people do not realize the monthly chance for women less than age 30 to conceive is only 20-25%. After one year of attempts, approximately 85% will have conceived. The most proactive method is to use a home ovulation predictor kit and have relations often within the six day preceding and including the date of ovulation.
Herbs ; supplements. At least 3 herbs have been proven in published studies to improve sperm count and motility: maca, tongkat ali ; mucuna pruriens. There is also evidence that ginseng, ashwagandha and tribulus may be helpful. Reliable standardized extracts are available. Other nutrients like zinc ; l-carntine/acetly-l-carnitine can help too. See http://www.Raysahelian.Com/fertility.Html for a summary of research. Read more...