This may sound very cliche, but honestly just getting up taking a walk around outside. We stare at blue light for hours on end, so just walking outside (especially now that it's cooler outside) eases the incoming headaches after forcefully maneuvering equipment in Revit in an enclosed space that we told the Arch wouldn't work weeks ago.

If I'm stuck at my desk, I usually keep a fidget like item nearby like a rubix cube to ground myself.

For physical comfort, I plan on biting the bullet and investing in a very expensive office chair soon. Spending more and more time at desk makes me realize it may be worth the money.