Dear CaptivatingCollages,
I took a look at your title tags as well as bottom tags, and I would say that that is where your main issue lies. You're doing a good job using the space allowance in your title tags, but you need to diversify those a quite a bit, and your bottom tags are much too short - you're allowed 20 characters per tag (!) - and aren't necessarily full key phrases.
When making tags, you need to get in the head of the customer. If I were looking for a collage like yours, I would probably type in something like: "collage art" or "mixed media collage". I took the liberty of checking and those searches yield 238,649 and 121,401 results, respectively. Those should be your first tags! You can follow those with specifics/alternative keywords and general uses. For example, I would make title tags for your black and white collage listing read like this:
<< Mixed Media Collage, Collage Art, Black and White Print, Mixed Media Art, Black and White Decoupage, Vintage Style Print, Unisex Gift>>
As you can see I am using may of the keywords someone who is looking for this type of purchase, but I am mixing up the phrasing because not everyone looks for the same thing. Moreover, words that don't exactly describe your product - in your case this would be "prints(s) - can and should be used because for one, not everyone is great with synonyms, and two, people looking for similar products might like yours just as much or better. Also, please, please stop using words like of, and, or, etc., - prepositions are a waste of precious real estate when it comes to tags, and don't count as keywords or parts of key phrases!
Hope this was helpful!