Make sure your description (App Store, Google Play, Steam or others) is the best it can be for a flat fee of US$10, including screenshots and related media.
When you do a lot of writing, you get tunnel vision. You are unable to see the mistakes in your own work. A fresh set of eyes can help make sure you've got it right!
An editor doesn't have to be someone you bring in after the plot is finalized. Editors can help develop ideas into stories, characters and dialogue.
You may have killer mechanics, amazing art and great programmers, but without a good story, the experience is incomplete! Now where would you find a writer...? ;)