Have you tried words like nature, scenery and landscape? I would type something into the search bar and see what suggestions it gives you. My current computer is very slow and the search bar doesn't do this, but if I had a faster connection, I'd give you suggestions based on this.
Also, it helps to mention the same words in both your titles and tags. Don't know if you're already doing this, but if you have "fine art" in your title, make sure it's somewhere in your tags, as well. Check your Shop Stats to see what words are bringing people to your shop. I also use Craftopolis.com to see what exact words are drawing people to specific, individual items. This requires a Google Analytics account, though.
Also, page 2 isn't bad!