Hi,
First of, if you want to perform a reset, make sure you go into Settings / Accounts / Google - make sure everything has properly synced up to date. That way when you factory reset your phone it will ask you during the initial set up if you would like to restore your phone to a previously synced date. If you say yes it will start the phone up and begin downloading all your previously installed apps. Photos, music, videos (media) aren't synced up, so I would recommend either moving them to a cloud storage or connecting your phone to a PC and manually dragging the files to the PC so you have them backed up. Once the reset has been performed, connect the device to the PC and move your media back.
Text messages are another thing that isn't synced - have a look in the play store for apps to back them up.
Finally, do you mind me asking why you are performing the reset? I only ask because there might be a quicker / easier method to take if you have an error on the phone.