There is not really a way to promote your gig the website normally shows top gig at the top off all results, it is up to the buyer to keep scrolling to see what else is on the other pages. I am a new seller and my best advice to you is to provide something that solves an issue. ( For example provide gigs that creat a solution for people who want to increase their twitter followers). This example the seller is solving a problem new businesses face when the just arrive on social media. Last advice is to choose the best keywords, these are very important and you are only allowed 3 and for some gigs more. When selecting the best keyword think like a customer who is typing in the search box.
Here you will see my seller profile