I'll let you in on a secret of mine. Cause.. I really suck at plain refined lines.. I don't know anyone who does this.. but...
Two layer it. Draw the sketchy line, drop the opacity to like... 30%, slap another layer and trace over it all neat.. Merge layers and BAM.. you have neat lines with shadows that hide any minor mistakes in the refined lines. Bwahahahha. I can't believe I gave up that secret. Here.. lemmie show you an example of something I've done..
Let's take an old pic since lately I've been coloring without lines so I just leave a sketch under and paint over it.
YAY! MINI TUTORIAL! How I prepare lineart - never seen before! Cause I don't always do this method, bwahaha.
First.. sketchy as shit (I do this because I add all details I plan to toy with.) Sketch with tablet (or in your case, use your pencil sketch and play with the brightness and contrast to fix up the coloring to fit with the refined lines so that the colors won't clash together - or suck the saturation completely out of it.):
Second.. add a layer at 100% after dropping the opacity of the sketch layer down and draw your lovely lineart:
Third.. Merge the two layers together!! (Make sure you kept a background layer under them to color on... if not, seperate the lineart from the background now after merging the sketch and line layer.) Awww doesn't this look whispy and refreshing now?:
LAST.. COLOR COLOR COLOR CLEAN CLEAN CLEAN! ...Yeah. Make sure you color your work under the lineart layer and be sure to tweak anything you see fit in the line art as you move along. And you'll get something like this..
I really hope that helps... if not, I wasted my time O.o; I wanna see what you come up with if you do it.