You should be tracking your ovulation by using ovulation strips as well as buying a basal body thermometer to keep track. You can buy the thermometer where the reg ones are sold. Once you get one go to fertilityfriend.com and it will teach you how to chart your temps. Also look into getting the book "Taking Charge of Your Fertility." Good luck
Most women will ovulate 12-14 days before the start of their next cycle. For example a 28 day cycle will potentially ovulate around day 14. My cycles are an average of 31-33 days and I ovulate around 21-22 days so I don't follow that pattern.
OPKs and temping are great help at figuring out ovulation.