Greyscale Coloring Tutorial

After being asked on VHR by Jinxy about why do i color greyscale, i tried to explain it, then gave up and decided to break it down into steps, and then decided what the heck, i may as well do a full blown tutorial.
So here it is. I recolored a lineart and template i already had, and hopefully broke it down into easy to follow steps for those people wanting to know either why i shade in greyscale, and then add color, or wanting to know my method of it to see if it differs from what they know/use.

Artwork is mine, touch and you will lose those sticky mitts.
Thanks to xxdark-wolfxx.deviantart.com/ for the stunning stock pic i used as a color ref