Another big one: Use the mouse from your shoulder/elbow, not your wrist. Keep the wrist stabilized.
Same with pencils, pens, and other drawing utensils. Drawing and writing from your elbow makes all the difference and suddenly you can keep going forever. And your lines look cleaner.
It's also generally accepted that people who "aim" with their wrist tend to need to warm up and take breaks more as it is more straining than using the arm.
It seems to concur with the conventional wisdom on art, piano and typing.
Does this truly work?
I remember stumbling on a page that advocated using shoulder and elbow movements to control drawing utensils, for the reasons you describe. I recall it looking pretty sketchy, "one weird trick" type, but I figured what the hell, it's cheap to try and my handwriting sucks. So I tried and tried, for many hours (EDIT: [0]), and observed that it's not only much more tiring than "normal" way of drawing/writing, it's also extremely imprecise. Sure, I can sort of draw a straighter line this way, but I can't control where it goes or stops with enough precision. And everything has to be bigger, because again, precision for normal-scale letter writing just isn't there.
Or maybe my body is just broken?
(Also tried this with a mouse, with the same results - everything takes too long, and keeping the arm unsupported is tiring.)
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[0] - I dug out my old notes; it was exactly 8.5 hours of focused, deliberate practice of drawing letters using arm and forearm for control, over the span of a month, on top of any writing activity I'd otherwise be doing. I may also have spent additional 1.5 hours on the aforementioned practice, but the notes aren't sure if that really happened (I tracked it in two systems, there was an entry missing in one).
As already pointed out, that's a very low amount of practice to change the technique. For piano, when learning forearm rotation, the point when it became much, much more comfortable to me than my previous way of playing was after roughly two months of practice, 10-12 hours a week. That's just my experience, but when I asked my teacher about not feeling improvements around the one month mark (40 hours in), he said that everything is progressing at an expected rate.
But, I'm curious: how do you place your mouse on the desk?
To me, there's one big difference between the paper and the mouse: The former sits in front of you, while the latter sits to the side.
I find it uncomfortable to move the mouse too much to the side, even though I use a fairly compact keyboard (MS Sculpt).
I've spent some time a few months ago trying to optimise my mouse situation. In the end, I went with a "gaming" mouse [0] for the high resolution and (relatively) low weight so that I can move it around with just my fingers. However, I'm not a very heavy mouse user, so maybe this helps rest the fingers.
I've also tried a vertical mouse, but the issue with moving the arm too much to the side was present, too.
What also worked well for me is a thumb operated trackball (I use a Logitech MX Ergo).
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[0] For the curious it's a Logitech G703. It was the best compromise I've found looking for a wide and lightweight mouse. Wireless is a nice bonus, it was barely more expensive than the G403 which is otherwise identical.
I don’t have any problem moving my stylus side to side.
When I’m working at my desk sometimes I end up shoving both keyboard and tablet to the left a bit, so the tablet is more in front of me. It’s not right in the middle like a piece of paper would be if I was hunching over a drawing board, though, it’s still distinctly to one side.
When I’m out and about with the laptop I tend to align myself more with the screen, so the tablet is distinctly off to the side. Never been a problem.
In my case, I use the keyboard much more than the mouse.
If I try to go back and forth a lot then I'm gonna either be constantly putting the stylus in and out of the holder, or typing with it between the fingers of my right hand, neither of which is much fun.
Out of interest, and assuming you use a tablet with extra buttons, how do you use them? Or do you disable them like virtually every other tablet user I've ever met :)
And yeah pressing too hard on the pen will fuck you right up :)
(so will holding it too tight, if an invisible person couldn't easily pluck your pen out of your fingers, you're holding it too hard)
I had a mouse once that was shaped like a joystick, so your hand was 'side-on' instead of face down. It FORCES you to use your whole arm, basically.