How can I pinpoint my ovulation?

Since being on the pill in between having my children i don't think i even know the signs of when i am ovulating!! If your cycles are quite regular i would go off your calander. It has worked twice with me and both times i have fallen pregnant in the first mth of trying. I just got my first BFP this morning and i still can't believe it, i think i'm in shock!!! Good luck and baby dust to you...