I agree with both ladies. I purchased the Clearblue easy fertility monitor and it works pretty well. It is a little expensive and you must purchase the sticks but it will definitely let you know when you need to "handle your business" with your hubbie :)
I can tell you whats worked well for me (3 times now). I use an ovulation predictor kit. I am a 28 day cycler, and I usually get my LH surge on day 11, but sometimes its a day or two later then that, so I find the predictor kit works really well for me. I am a big fan of the clearblue easy digital brand. Its a bit pricier, but I find its easier to read. Anyhew, from the day I get my positive, I know I will ovulate anytime in the next 12 to 72 hours, so everyday from the day of the positive for about 4 days we BD. I have also started using the preseed (I ordered it from www.preseed.com). Its a lubricant that matches the natural fertile mucus we produce when we are fertile, as that can be a bit of a problem when we are in late 30's.
Many women have conceived BD'ing every other day, but I have found every day works best for me.
My OB also told me (he is also a fertility specialist), that not going to the bathroom afterwards, but just staying put on your back, hips and legs slightly elevated really helps solve a lot of fertility issues. I do that as well, and its worked!
Best of luck in getting a BFP!!! Sticky baby dust to you!!