I am exactly the same my AF are due so if I get them I want to start seriously trying. I got told 10-16 from the first day of AF do it every day but depends when you ovulate. I have no idea when I do so that is what I am struggling with at the moment. I have also read things like doggy, missionery (man on top) or sideways is the best - it just needs to be in a position where it can reach your "good bits" the most. I have also been told don't go to the toilet for 15 minutes afterwards as let it all get in there!
Sorry if too much information but that is a few tips I have been told.