How did each boys leadership skills help the boys?

Piggy's leadership skills were purely based upon knowledge. Among the boys, he wasn't appreciated and was often made fun of. Ralph, however, knew that Piggy's ingerent intelligence was integral.

Ralph skills can be found in his sense of organization and inherent ability to communicate with the other boys.

Jack, though portrayed as a rebel and ultimately evil character, was also looked up to. He had the ability to inspire the hunters, who it seems, would do anything for him.