Before flashing ROM or after rooting your device make sure you have back up to recover your important data and files.
This requires Memory card.
Open stock app "Back up & Restore"
If you dont have, DL this and flash via CWM recovery:
http://www.mediafire.com/file/swuiw0s8qcmzsca/Stock+Backup&Restore(KK&JB).zip
Goto "Personal data" mark check to all data files you want to back up and press "Backup to SD"
Now if you wan't to back up your installed applications, go back and go to "Application" then marck Apps you want to back up then press "Backup to SD card"
Now you are done.
To restore simply goto "Restore" and select the saves you want to Restore.

This requires Memory card.
Open stock app "Back up & Restore"
If you dont have, DL this and flash via CWM recovery:
http://www.mediafire.com/file/swuiw0s8qcmzsca/Stock+Backup&Restore(KK&JB).zip
Goto "Personal data" mark check to all data files you want to back up and press "Backup to SD"
Now if you wan't to back up your installed applications, go back and go to "Application" then marck Apps you want to back up then press "Backup to SD card"

Now you are done.
To restore simply goto "Restore" and select the saves you want to Restore.