Be sure to stay active on Fine Art America: join discussion, contests, etc.
We have an entire Marketing section for you to utilise to help sell your work. Try using those tools to help you.
But the best place to start is telling your friends and family.
Search takes into consideration many different factors when determining the sort order of the images.
It takes into consideration:
1. the relevance of your image keywords
2. the number of times an image has been sold
3. the number of times an image has been favourited
4. the number of times an image has been commented on (by others. Your own comments on your work do NOT count)
5. how long an image has been on the site
6. the number of times an image has been featured in a group
There are more than 25 different criteria that the search engine evaluates.