If you are regular on your cycle, you are likely to ovulate on 14th day from your last period. So DTD during this period/week maximises your chances of conception. Cervical mucus will also help you to predict your most fertile days. Changes in CM will indicate the days leading up to ovulation, and sexual intercourse during this time will ensure that spermnourished by fertile phase CMwill be present when the egg is released. Look for white or cream coloured, thick to slightly stretchy, and egg white resembling CM, it indicates that your body is highly fertile in those days.
After ovulation, an egg is only viable for about 24 hours and sperm can live in your reproductive tract for up to 72 hours. So for the very best chance of getting pregnant, a couple should have regular sex every day for the 5-6 fertile days leading up to ovulation, and on the day of ovulation as well.
Good Luck!!!