By holding Shift. I find it less confusing than the stateful Caps. I never get surprised with having typed in the wrong case because Caps was on or off when I expected otherwise. Just put that pinky on Shift while you type. Release when you're done with upper case letters.

Maybe I’m just passive or don’t frequently declare constants, but I never need it. As a vim user, though, I love prophylactically mashing the caps lock esc.

Just remap caps lock to caps lock!