A healthy man should not need to do anything. Just make sure you're holding it at an angle obtuse enough to allow you to cycle the bolt without dropping the rifle down. I've seen a lot of folks try to shoot these with their eye right behind the bolt, as though there were a scope there. Your eye should be back and the rifle should be resting firmly but comfortably in your shoulder, but not jammed into the bone while you're crooking your neck forward.
Think about it for a second, and forget all the internet nonsense about the big recoiling Mosin. This is a rifle that weighs EIGHT POUNDS or more, depending on the wood in the stock. It's firing a cartridge no more potent than standard .30'06. The math simply does not support this notion that it's a bad recoiling firearm. The problem seems to lie in the fact that the stock ergonomics are very different from modern American hunting rifles.