On a recent design project, I spent quite a bit of time sketching. They weren't fancy.
I just used plain printing paper and a ball point pen (wasn't even a nice one).
The primary purpose of the sketches was not to show off my sketching abilities. It was the fastest skill in my tool box for rapidly generating ideas and exploring them in detail.
Given that this is my purpose, any other 'improvements' to my sketching process should not slow me down or make me more 'attached' to my ideas. This is often the case when we start to make things look more real than they actually are.
Thus, I am simultaneously amazed yet wary of sketches that look like they should be framed. The kinds of sketches that look like they were produced by architects. This is not the road I want to take.
Any skill can be improved, and should be improved as long as you have a reason for it. I'm thinking of giving my sketching process an upgrade. At some point, I may want to show users or product managers my sketches. The better they can communicate my point, the better off I'll be. However, these upgrades are probably more like supplements.
I'll still retain my original sketching process, and create more refined sketches when I need to show them off to people.
Here are some links that I've found interesting or useful:
How to draw quick useful UI Sketches - Lane Halley
5 Big Tips for Sketching on Paper
Sketching User Experiences - Bill Buxton
Have a favorite resource for learning how to sketch? Let me know below!