depends on your form, where your weakness are, etc.
typically yeah squats, cleans, jump splits (some people do this on a smith machine)
shuttle sprints.
are you a leaper or a power jumper?
power jumpers gather and go up off both legs.
improving your jump form can help if it isn't totally refined.
power jumpers can also benefit from rapid-fire hopping and stuff to improve your muscle timing in your calves. working on your ability to power back up after coming down without a gathering again. builds balance (via your core) and develops fast-twitch muscle fibers.
shuttle runs help in a similar way and also help a lot with the plant/gather teaching yourself how to do so with minimum muscle engagement so you can explode up from it, etc.
do a lot of stretching for your core area, do a lot for your groin.
if you are a leaper then doing alternating split box hops and such have a similar effect working fast twitch muscle fibers and reaction timing in both legs, plus helps to work on form and balance (again via the core.)
it's late...i'm tired... start with that stuff.