Also, list your name in your tags, the colors you've used (many art buyers shop for specific colors), and with abstract work you can also add feelings/emotions/shapes, etc. For instance:
blue, yellow, green, orange, mystery, mysterious, contemplative, pensive, circle, round, orb, sphere, . . . (just examples; not related to your actual images)
You can use any word or phrase that legitimately relates to your image. You never know how a potential buyer might search -- best to cover all your bases.
Here's a link that may help -- http://1stangel.co.uk/fineartamerica/?s=keywords
You'll find more info under the HELP tab, on the main discussion page. Here's that link:
http://fineartamerica.com/discussions.html?tab=permanentdiscussions