Make Dropbox app upload in background without having to open every 10 minutes
You can't. There are restrictions with iOS multitasking that prevent apps like this from running all the time. You might be able to bypass this by jailbreaking though.

Also, apps can't bypass this on the App Store due to guidelines such as:


  2.5 Apps that use non-public APIs will be rejected


Source: https://developer.apple.com/appstore/resources/approval/guidelines.html