7th grade cheerleading tryouts help?

Hi! I'm trying out for 7th grade middle school cheerleading next year and I need some advice,help,etc. I have done non-competitive (recreational) cheerleading in the past. I also did gymnastics for about 7 years! I quit 2 years ago so I can't do the really hard tricks anymore, so the basics. (cartwheel,roundoff,handstand,sidesplits… walkover,front walkover,kick leg to head.) those kinds of things. 1. How can I work on my jumps. 2. How can I get my legs more out (straight) when I do a stradle jump. 3. How can I get higher off the ground when I jump. 4. Advice, help anything ! it would be best from former or current 7th and 8th grade cheerleaders!! (btw I don't have a trampoline so can't practice on that and I don't want to take cles again cause I'm so busy!!) Thanks!!