I know a little thing about fiverr ranking ones gig higher.
-Focus on key words in the title of your gig. Most buyers search for what they need exactly do fiverr respect gig's with the keywords of what they offer in title. Eg "seo article" "graphic design".
-Number of times user interact with a particular gig. Fiverr care more about making profit so they believe that gigs that get interactions means more income for them. Gigs with more interaction shows up more often than those that people refuse to click.
-Fiverr gives more impression to video than it does to picture in gig description. I changed to a video in one of my gig's and my impression suddenly increased great time.
- Fiver rank gig's for user that stay online often higher than sellers who just come around once in a while.
- fiverr shows your gig more often if you make sales with the people who contact you.
-and lastly, I know that fiverr works to show relevant tags first.