My inking technique is rather simple, I try to hold a firm & constant line in one movement. Never do I go back over the same line( unless I make a mistake...which I OFTEN MAKE WORSE, or I need a thicker line) I like to keep it simple!! Like an anime cel or like drafting.
I use different pens with different line weights, depending on the details.
I use several different makes of pens:
Pilot Fineliner (about a 0.3)
Staedtler Triplus Fineliner (about a 0.5~0.6)
Lots of Alvin Penstix(0.3, 0.5, & 0.7)
For very fine lines I use Sakura Pigma Micron
(in 0.1 and 0.2).
The original Lilo & Stitch was a fantastic movie. I saw it during my plane trip back from Kauaii, where, ironically enough, most of the action in the movie takes place. You should watch it sometime, as I think you'll like the designs of the spaceships, aliens, weapons, and other science-fiction elements.
My best thumbnails are done at a very small size, too. I then scan, rearrange, and print them for final tracing and inking.