Many people have different preferences for saving and restoring for a full reset.
I can only offer a few, but certainly check your Google account's Sync settings, if you have Google+ enabled that will store the media you have selected.
Many like me will save via media via usb to a pc. I also use Dropbox, but Drive or other cloud storage is good.
If you have a Samsung, make sure it is syncing everything in the account settings, and avail of Samsung Kies on a pc, though it won't save everything.
Many use an app like Helium to save app info as well.