One thing that I always wanted in the mobile app (phone or tablet) is to see the status of the current note while I'm working on it. Is it synced with the server? Is there any pending changes that need to be synced? Or is it currently in the process of syncing with the server?
This would be shown in small button, somewhere in the top bar. Tapping the button would start a sync process. In other words, it act in a similar way as a Save button that also show you if the document needs to be saved or not.
3 states needed:
- Need to sync
- Currently syncing (maybe with an animation?)
- OK: All changes were pushed to the server (sync target)
This would help reduce the main source of conflicted changes, by providing clear visual feedback. Too often I've had conflicts while working on my phone, then closing the app thinking that my changes were sent on the server, then editing that note on another device, only to discovers hours later that not all my work from the first device was sent to the server, and now I have to merge a bunch of conflicts. 
If you want, I can provide some visual mockups for what I have in mind! 