For the ecommerce sites I'm responsible for, I make sure every product page has a unique title and meta description. Took me a slap month to write them for 2500 products on one site, but I did it - and I had the client put in custom coding that would allow me to do it, and we wrote a script ourselves that would alert me every day via email whenever the client added a product, so I could go in and tart it up.
I paid extra attention to meta descriptions, to try to entice the viewer to visit the page.
It paid off big time. Not right away, but we have easily three times as many indexed pages bringing in traffic than we did a year ago.
That by itself will go a long way, because many ecommerce platforms are built to cut corners on such things.
I pay attention to my internal linking, and we have blogs and videos featuring products, and I link (judiciously) there too.
It doesn't hurt to go into some of your inner pages and fetch as Googlebot (from GWT) either, to make sure you know what Google's seeing.