*buy a UPC code for each item, they are cheap and give you one more piece of unique data to add to your sku description
*keyword-stuff the name of the image you upload (best_green_widget.jpg)
*List on Amazon and Google shopping, try to get as many star-reviews as possible (you can do this with fiverr, or by temporarily cutting the price very low and having friends buy+review)
*include the same keywords that appear in Google's "related searches" link when you search for you target term in G Shopping
*Have multiple people with G+ accounts click the "Add to Shopping List" in Shopping Results, Add a (SEO'd) Note, and use the "Share" function to publicly add to Wishlist