You know it's amazing that no matter how long you've been drawing you can always find processes and ways to improve.

Lately, I'v been sketching with brush pens and medium tip markers. Which has been a great confidence builder. Sketching with a marker makes you be intentional about the lines you put down. I mean, you can't do alot of scribbling with a marker unless you like looking for lines that have bled together. Now it's nothing wrong with scribbling, but if you are like me, short on attention span and impatient, you may want to consider this marker thing.

Sketching with a marker allows me to get to my finished product sooner without all the erasing and cleaning up. When well rested I have vision clear enough that I don't thumbnail, but when I don't get enough rest I'm lucky to get any vision at all ( which is common since I have a wife and three kids under 4 years old), so I do thumbnails as a way of fishing for ideas. But, while fishing sometimes I get caught up in details instead of focusing on the gesture and design. Not so with a marker, once the line is wrong it' wrong, but in you mind you accepted this before you start, so you don't really get carried away with it.

Now when I sketch with my pencil I sketch like I have marker with a more finished, intentional, and accurate line. And it usually takes drawing one or two lines and in less than 15 sec the bulk of the work is done (if I know the character).

You should try it if you want to increase your speed, confidence, and accuracy.