There was a short discussion in this forum last year about getting rankings in Google Merchant Center or Products or whatever they're calling it this week. The thread was at [webmasterworld.com...]
In the title of my products, I have the product name along with the model number in the different configurations it can be found, i.e. "Acme Widget, Model XYX-123, XYZ123, XYZ 123".
In the description, I'll get in the price first, then a brief description that includes the widget name, model and any other item/product that it applies to ("Acme Widget XYZ123 for SomeCompany's Thingamajig"). I'll then finish with the three variations of the model number again.
I don't know if this is good or bad. Sometimes I'm ranking right on the first page when I search for the widget, sometimes on the second or third page, and sometimes not at all.
What I do notice is that the big sites who've been around for eons seem to get the top spots almost by default.
I really don't know how to "optimize" the listings beyond this.