Timing of intercourse is when you try to make love only within a day or 2 of ovulation. The problem with timing is that has never been shown to improve your pregnancy chances. In addition, many women often do not know the exact day that they will ovulate and studies have shown that even in women with regular cycles, ovulation can possibly happen any time.
You are probably not improving your chances of getting pregnant if you wait with intercourse until the ovulation predictor kit the OPK has become positive. The problem with the OPK is that by the time it's positive you may already have ovulated, and sex after ovulation is unlikely to get you pregnant. Waiting until the BBT temperature has gone up is even worse, as the temperature goes up after ovulation.