a while back I had the same problem. As people have probobaly said turn it on and off again , it might be a pain doing that all the time. So I suggest deleting all the apps you don't need/use mail and photos too.So you have as much space as possible.Update to the latest IOS if have'nt already?
Hope I helped.
Frozen or unresponsive iPad
Resolve these most common issues:
• Display remains black or blank
• Touch screen not responding
• Application unexpectedly closes or freezes
iPad Frozen? How to Force Quit an App, Reset or Restart Your iPad
iPad: Basic troubleshooting