There was a topic on this before, I forgot where it's located, but you've got to cut the distance, make later take-offs, and attempt to dive less.
For most kong vaults I'll take off three or four feet, and some occassions even five, but for additional height + distance on the exit I'd practice a double-step or split foot launch. The idea is to not dive at all but actually use your hand plant to further increase your height/distance. Practice this with a Monkey Vault, you'll find yourself popping an extra foot or two in almost no time.