I agree with the Wacom as far as tablets. Photoshop is the graphics and image manipulation software of choice - although if you want to do some realistic painting effects, check out Painter (now Painter X). I don't have this latest version, but back in the day it could simulate different types of media (watercolor, pastel, oils, etc.) and different papers. Can't imagine how much fun this new version would be.
As far as technique, I'd like to recommend one to you if you like anime:
Draw your subject
Scan it
Pull it into a vector program (such as Illustrator)
Trace the lines (using the pen tool and least amount of points possible)
Experiment with different stroke types, like marker, brush, straight, etc.
Save it
Open in Photoshop
Make sure your drawing is on the top layer then set its mode to "multiply"
Create a layer beneath it and start coloring!
It's as if you were working on a traditional animation cell.
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