I'm not splittin' too much by hand anymore, but I did my share. I always had a sledge hammer, 3 wedges, the "blaster" (which was the head of a monster maul that the handle broke off of), an axe, and 2 mauls.
I always set the round to be split on top of another round, or sometimes 3/4 inch plywood or something like that, as I think it made better than on soft ground.
Sizing up the round is important. You know, lookin' at it, contemplating the grain, the knots, the twists, etc. so as to not expend unnecessary energy splittin' the dang thing.
It's the psychology of splitting ya see, I'd throw the nasties off to the side often for another day, that way I could breeze through the easies first and not tire out so quickly.
Spread legs, raise implement of destruction, and come down on the thing with sufficient force. You see, ya don't always need to pound away with a maul, cuz some stuff splits easy with a lighter axe....hence, the psychology of the whole thing....
Some times with nasties I'd just go ahead and fire up the chainsaw and saw straight down into the thing a third or half way, then set the wedge in there....yep, I'd saw into 'em and cheat like that if I had to
Wear good solid jeans, or shin guards would be better, like soccer players wear, but jeans and heavy socks usually worked. However, I'd always get a shin bruise somehow.
Flying metal from wedges can be interesting, I'd do wedge maintenance too, with the grinder, getting potential shrapnel ground off the things.
Oh yeah, and always, always, would wear gloves!