the overall is actually a pretty good guideline as to what the guy's passing, faceoff, attitude and stamina are going to be.
then, the formula is pretty simple, forwards: the key attributes are, in order, offense, speed and shot. defensemen it's defense, strength and speed, in that order.
Offense, defense, shot power and shot accuracy go up thru BOTH practice and games, so a guy with even decent potential will progress in those categories.
Speed, strength, passing, faceoff, attitude and stamina are pretty much a case of either got it or don't, because they go up more slowly - only through practice.