What are some good drills, warm-ups, exercises and jumps for a high jump practice?

I need to work on getting my form down, and also increase my all around high jumping ability. I have gained 4 inches this season and can now clear 5'4 and my goal is to clear 5'6 or 5'8. What are some good drills, exercises, warm-ups, jump, etc., to work on at practice. We have a high jump pit, bar, bungee, and box to jump off, by the way.|||butt kicks