I agree on the stop breathing advice.
Beyond that, no real solution except keeping the inside cooler than the outside, which isn't too practical either.
Condensation didn't form on the double pane windows (like Seitz acrylic windows) I've had, so in my Unimog and first Sprinter, which had a lot of the wall space covered with them, the problem was proportionately less.
My real reason for posting is to suggest carrying a small squeegee, the sort they sell for shower wipedown, if you have open enough open space to use one. We carry one in our current Sprinter, and it works well to move the condensation to one edge, where you can get it with a terrycloth rag. Saves time and, if you're clearing windows, leaves the windows way less splotchy than if you wiped all the water off with a rag.