Note that Order cancellation has a very high negative impact on gigs in terms of ranking, order completion and among others.
Here are tips to know; Make your gigs easier for buyers to understand, create gigs you are only very good at, communicate to your buyers clearly and make them happy. The more sales, positive reviews and impressions you get, the more you rank up, similar to google ranking. As a new seller, don't be discourage, keep your heads up.