Have you tried charting? Some women learn to better time intercourse when they're charting. There's an ovulation tracker here that you might find useful:
http://www.medhelp.org/user_trackers/gallery/ovulationIf you have an iPhone, you can also try the My Cycles app:
http://www.medhelp.org/land/my-cycles.
Good luck and baby dust!
Are you tracking when you ovulate? This can either be a big help or a nightmare because sometimes its not always the right time to get down into the act but if you know when your ovulating then you know what your changes are of it happening. You could also talk to your doctor about getting a little help from a fertility drug.
Good luck with TTC and hopefully it happens soon for you. BABY DUST COMING YOUR WAY:))