Flashing a Recovery Image

Download the latest recovery image (or not) for your phone model. You can get them from the CWM site. Note, for my nexus for, the Mako recovery image (6.0.2.0) worked, while the Manta recovery image (6.0.2.3) did not. To flash the recovery image,

$ fastboot flash recovery /path/to/yourrecoveryimage.img

It should only take a few seconds to do this. Once completed, you should see a message similar to

sending 'recovery' (XXXX KB)... OKAY
writing 'recovery'... OKAY

If you see a message saying FAILED, it's probably because you haven't unlocked the bootloader.
You should now have an unlocked phone with a custom CMW recovery image that you can use to perform nandriod backups. This only gets us halfway to our goal, however, which is achieving root access to the device.