How To Make a Backup of Your System, Apps, and Data

The first thing you should do—before you ever make a big change to your system—is back it up. First, we'll make a Nandroid backup, which is basically a image of your current system. That way, if something goes wrong, you can restore your phone to exactly the way it was before you started tweaking. This will save you a lot of hassle if something goes wonky (which, let's be honest, can happen often). To do this:

1. Reboot your phone and enter recovery mode. This is a bit different on every phone, but usually involves some permutation of pressing the power and volume buttons at the same time.
2. Head to the "Backup" or "Nandroid" section of your recovery mode. The default settings should be fine. If given the option, give your backup a name that helps you remember what it is (like "Pre-CyanogenMod Backup 01-17-14"). Confirm your backup and let it run.
3. Wait for the backup to finish. This may take awhile.

I also recommend making a second type of backup: your apps and settings. If you just unlocked your bootloader and wiped your phone, you can skip this step, but any time you flash a ROM in the future, you'll want to back up your apps first, since you may have to wipe your phone before you flash. With a backup, you can easily restore those apps and data after flashing, making the process a lot simpler. We recommend using Titanium Backup.

This is different from a Nandroid backup because it just backs up the apps themselves, which you can then restore on any ROM you want. Nandroid backups take your entire system as it is, ROM included.

Note that you'll need to be rooted to use Titanium Backup.  To perform a backup in Titanium:

1. Open Titanium Backup and grant it root permissions if it asks for them. If it experiences any problems with root, it'll tell you right now.
2. Tap the "Batch" button in the upper right-hand corner (the one that looks like a little checkbox). Scroll down to the "Backup" section and find "Backup All User Apps." Tap the "Run" button. This will back up any apps you've downloaded from the Play Store, and their data. (You can try backing up your system data as well, but I find this usually doesn't work very well).
3. Wait for it to finish. If you like, you can also sync these to Dropbox.

This may seem like a lot of unnecessary backups, but trust me: it's going to save you a lot of time in the long run. Now if something goes wrong, you have a nandroid backup to fall back on and don't have to start from scratch. And, when your ROM flashes successfully, you don't have to start re-downloading and setting up all your apps yourself because you can restore them with Titanium.