Force quit the app
Double tap the home button, or swipe up from the bottom of the screen on newer devices, to open the app switcher and swipe up on the app to force quite it. This can resolve many problems.
Restart your Device
A lot of issues are easily resolved by simply restarting your iPhone or iPod Touch. If you are having problems, try this first.
Reinstall the app
To reinstall your app first delete it from your device, then go to the App Store and buy it again. You won’t get charged if you previously bought the app.
If the app crashes (i.e. you’re kicked back the the home screen unexpectedly), you can access the crashlog and send it to me, to help me debug the issue. See here how to get to your crashlogs: Accessing Crashlogs
Redeeming Promo Codes
To redeem a promo code go to the App Store and click on the little downward pointing arrow righ of your Apple ID on the top right, then click redeem. Enter your code and confirm.
Help with a specific app
If you have a question to a specific app, you can check out the FAQ for the specific app in question: