My understanding is that what works for a person varies, but here's some of the approx. dozen changes that I ended up making for myself (sorry have to be quick right now):

* lower keyboard shelf so forearms could be parallel to ground. I've found many desks can be lowered. one place, I found the mount for the detachable commercial-grade desk legs matched that of some lower side table in our lab area; so, in a late-night operation, the table used for lunch catering trays got strangely taller, and I suddenly looked strangely taller next to my desk height.

* wrists straight in line with forearms, as viewed from both side and from top. (I actually found my first-in-ages typing soreness briefly last year, when I used some laptop with a numeric keypad, and i realized that one of my hands was twisted to the side awkwardly to keep the screen centered. fortunately, that was only for a couple days, and i was able to switch back to a sane laptop

* some people like wrist rests, but others say wrist rests encourage bad positions or pressure; i tried them then switched to without, but i suppose they might work for some people, and i don't know the research

* both keyboard and monitor straight ahead of torso, not to one side

* maybe eyes even with top of monitor (this advice might've been intended for 13-17" 4:3 CRTs, and I'm not really good about it)

* arms should hang comfortably at sides. if I can't get a chair without armrests, usually they can be removed with a few bolts.

* feet flat on the floor might've helped

* some people benefit from typing breaks. and also from vision breaks, and stopping to focus on things in distance. i didn't seem to need either for any kind of discomfort (though I am a bit near-sighted, so maybe vision breaks would help)

* stress seems to contribute

* pressing simultaneous-multi-key combinations with the same hand, especially if stretching/twisting/straining the hand, is bad. one big thing I did with Emacs is switch from holding down Alt for Meta, to pressing and releasing Esc (except for Meta key combinations I might be pressing many times, like for undo or for incremental search, in which case I could hold down Al). I also tried to use other modifier keys with two hands -- one hand for the modifier, the other for the non-modifier.

* there was some of talk about the RSI from switching hands back and forth between finding the mouse and finding home row. Also, Sun used this Mouse Systems mouse with an optical pad that has to be placed, rather than maybe the body naturally finding where a good area of travel for the mouse is. And the mouse buttons could've been easier to press.

* The Sun keyboards also had a set of special function keys for things like copy&paste, and I don't know whether moving off home row to reach for those and then go back to find home row is a significant strain.

* (Later on, I switched to Trackpoint keyboards, which let my fingers stay around home row, and requires only very slight movement and pressure. I vaguely recall first trying Trackpoint when in a very stressful situation, and i did get some soreness in my Trackpoint finger, IIRC, but it soon went away. I mentioned this to the Trackpoint inventor, and he seemed unsurprised, but maybe slightly sad that Trackpoint wasn't perfect in all ways. I suppose the newer designs of Trackpoint cap might also help, rather than the hard sandpaper one I was probably using at the time. Today, I put 15-year-old new-old-stock Trackpoint keyboards into 10-year-old Thinkpads as my primary workstation.)

* (I also now have a "lectern" standing desk, $200 on Amazon, that fits a laptop, beverage coaster, and a small device like smartphone or embedded device. I never bother to adjust the height, but it's good to stand for chunks of time, and it can be moved around to wherever the light is good, view out the window, etc. Some partners and customers require videoconf apps that I don't trust on workstation, so those go on an iPad that gets put on a little arm clamped on back of the lectern as needed; and then the arm is mostly hidden when not in use, by clamping upside-down to the back of the lectern.)

* (Today, I don't have to think about it, and I just do whatever is comfortable/natural, which I suspect doesn't look like the good posture that the earlier bullet points in this list might sound like. but I suspect they're good starting points.)

I want to emphasize that these things are preventative measures, and based on folk wisdom. It might be worthwhile to bring a workstation ergonomics expert through office proactively (after Covid), to look at the setups and practices of anyone who wants. And if anyone is already seeing symptoms, it's crucial that they not try to "work through the pain", because that can cause permanent damage. Including permanently no longer being able to type at all, and/or chronic pain. If you're having trouble, it's important to find a doctor who'll take it seriously, and then to take the doctor's directives seriously.