When I was 10y old I got to cut a thingy for my younger sister to choose. A third had sprinkles so I cut just that third of. My mom implied I was gaming the system but I said my sister is free to choose the bigger one if she wanted.

It was a gambit but I got 2x bigger piece.

That's the best tactic for sharing. I still like do to it that way (except when I'm a hungry, greedy goblin. Then i just may take the bigger piece).

Also the tactic of the exceedingly rare "PE coach with a brain" when they are doing a team sports unit; it's much quicker than the usual draft process.

If one the "captains" is being a douche, the less scrupulous coaches will spring the second half on them after letting them pick, but then the less athletic kids catch hell from the now-angry douchebag and get their asses kicked in the game.