I had similar questions a while ago !
For me, I do my best to stretch and draw with my fingers or whole arm - very rarely my wrist. I do my best to sit up straight as well.
If you draw digitally, make the zoom tool your dog. Seriously. Avoid leaning in on the screen whenever possible, this helps both your eyes and your back. If you draw traditionally, try to draw bigger as opposed to smaller. Your strokes become larger and less wrist-based.
Regardless of how you draw, having some kind of stand or incline to draw on is super great. It makes it easier to maintain correct posture while also giving your arms some rest. Wrist braces are great if you already have a repetitive stress injury, but it's better to avoid the issue altogether. 
I personally have one (1) cup/can of tea or small energy drink and then drink exclusively water after that. I haven't done any Science Experiments to figure out if it makes a difference in my pain, but it probably can't hurt to limit my non-water intake. I also take an hour break in the middle of my workday with smaller breaks roughly hourly so that I'm not doing fiddly dexterity stuff all day.