You ovulate 10-16 days BEFORE the start of your period. For example, if your cycle is 30 days long you will ovulate between cycle day 16 and day 20. SOME women get "egg white" cervical mucus (throughout the day - this is very different from arousal fluid and not to be confused with semen). Typically fertile cervical mucus will be present for 2-5 days around ovulation. This fluid will be clear or slightly cloudy, it will be either very wet (almost watery) or resemble an egg white. The rest of the cycle it may be creamy, sticky, pasty or dry. Taking 2g of Evening Primrose Oil (from day 1 to ovulation), daily Omega Fish Oils, and drinking 2L of water per day can improve cervical fluid. Because not ALL women notice this change in cervical fluid (often it is internal or short lived), you are ALWAYS best to follow the rule - "you ovulate 10-16days before your next period". You want to have intercourse in the 3 days before ovulation and on ovulation day - at least 2 times over this fertile period. You should lie down for 30 minutes after (with hips SLIGHTLY raised if you wish - raise them too high and you will actually prevent the sperm from entering the cervix though). Sperm quality is best in the MORNING.Typically sperm live for 24-48 hours once inside the cervix and womb. (Over 300 million sperm enter the vagina, but only 2 million will make it through the cervix). Therefore, as long as you lie down for 20-30 mins after it does not matter which time of the day you have intercourse. Every other day/every 36 hours is sufficient to improve your chances of conception. Taking your Basal Body Temperature can also tell you after you have ovulated (low before ovulation, spikes 0.5-1 degree higher the day after ovulation, drops low again the day before your period starts). Some women also use OPK, Ovulation Predictor Tests/Kits. Once you get a positive ovulation test, you are fertile for between 24-72 hours. You should have intercourse the day of the positive test and the 2 days after. Note that ALL intercourse can be attributed to intercourse during the 5 days before ovulation, although it is rare for sperm to live this long in the female reproductive tract.