Where to start?

Hubby and I have been TTC for about 6 months. I had a copper IUD for a little over 3 years when I had it taken out. I have very regular periods. I want to learn how to track my ovulation more accurately! Where do I start?? I know about basal body temperature reading, but where do I get that kind of thermometer? What else do I need to do? Hubby is feeling discouraged (24) because he has made it this far and never had a child of his own. He has a daughter who turned out not to be his biologically. They were trying to have a baby at one point. He feels like he may be infertile or something. Should we do fertility testing? I'm turning 27 next month and I NEED another baby. Mine is turning 5 in November, and his daughter is 2.