Approval is not guaranteed
Just because you develop an app doesn’t mean it’s automatically going to get approved by Android and/or Apple. In fact, the San Diego Foundation had to introduce a simplified version of its app to ultimately get it approved for the iTunes store.
To give your app a better chance of being approved — and to make sure you aren’t investing in something that won’t go to market — Back suggests looking at functionality that already exists on most of the apps that have been approved. Things like making sure the bells and whistles fit in the architecture and infrastructure of Apple or Android, going through tiers, utilizing push notifications, etc., are what mobile providers look for.
Solicit feedback
More than anything, an app is an engagement tool. So use the feedback you get from your constituents to improve the mobile experience.