Welcome to HCM. There are many factors involved in successfully conceiving. Your intercourse should be timed between 12th to 18th day of the menstrual cycle, 1st day being the day on which she starts menstruating. Your sperm count
has to be adequate, with good motility and of good quality. You wife should be having regular periods with ovulation. Her vaginal PH should be favourable for the survival of the sperms.There are still lot of other conditions. Best is to consult an infertility
Specialist, and get a thorough investigation done of you and your spouse, and if required necessary corrective steps could be taken.