Adding Colour

I have been drawing single colour portraits with pencil, charcoal and chalk. Recently, I began to use pen to draw with. Yet, in single colour. It's black on white or white on black.
However, this time I think am confident to add colour to my work. And since am using pen its proper to add colour. This is my first work, adding colour to my portrait drawing.

Still in progress and to be completed in few weeks.