Hi Wag,
I sell gorgeous naked women, you'd think they would be flying off the shelf.
What gets someone to your site, what makes them stay and what makes them buy can be like walking through a minefield to us non-marketing experts. Don't let frustration or confusion pull you down. There are some incredibly awesome soloists very willing to help.
I've recently plugged in to Google Analytics and found that it really delivers the info you need. Once you wrap your head around what it is telling you.
Before that I was relying on my website CPanel stats.
When you find the marketing holy grail make sure you share it with the rest of us mere mortals
Cheers