@Jennyann Ok, that makes sense! As annoying as it is to have to buy a pen display (Cintiq or equivalent), I couldn't seem to make any headway with sketch strokes until I did so. And the Kyle brushes that come with Photoshop are good. I still can't make the same strokes in digital that I can with a pencil, but they're a lot closer now than with an Intuos. And with your nice sketchy style, that's going to be important.
Another possibility is to scan the sketches and then adjust or fill with digital washes.
I took the backgrounds class, and it's a bit more about positioning characters in perspective and dramatizing their interactions than it is about backgrounds per se. It was useful, but not exactly what I was expecting. Hope this helps!