For the greatest likelihood of conception, intercourse should occur in the days leading up to ovulation. Ovulation occurs approximately two weeks prior to the menstrual period, and can be detected by the presence of slippery vaginal mucus. Young, fertile couples who have intercourse at this stage of the female cycle have around a 20% chance of conceiving in any given month.
If you have not conceived after a year of unprotected sex, ask your healthcare professional to investigate whether any issues are present that may be affecting your fertility. It is important that the fertility of both prospective parents to be assessed.
Note that infertility may involve complex issues and is not suitable for self-treatment. Your chances of a healthy conception and healthy pregnancy are best enhanced by professional, specialist care.