Ah, lineart. A skill of its own.
I got my girlfried to show me the basics of lineart and traditional inking, since I wanted to improve in that part as well. here are my first two tries:

I'll give both  of them a digital colourpass now, guess the results will be here tomorrow :) 

Before those I didn't do much lineart with pens or ink. I tried it a couple of times but never liked my results. I guess I'm  a bit spoiled from digital painting there, since it is hell of a lot faster and I often lost patience.  But it is a artistic skill like any other and should be learned to a decent degree as any other. You never know what kind of style a customer might want or with what kind of artists you'll work together some day :)