I remember reading somewhere that one of the big name gyms who is known for their jumps (Spirit of Texas or Stingrays) spends at least 20-30 minutes EVERY practice on jumps. I tried doing this but kept making other sections priority so jumps would get forgotten about.
Easiest fix I've found was to incorporate jump exercises and t-jumps/TT jumps in to your warm-up. As soon as you are done stretching, go straight in to straddle leg lifts and then perfectly sync'd standing leg lifts (not kicks).
Arms to T 5,6
Head look 7,8
Lift leg 1
Leg snap down 2
Lift leg 3
Leg snap down 4.... etc.
Clean on 8.
Then we do 3 perfect T-jumps to warm up the legs and timing. Then approximately 10 TT's with minimal breaks btwn. Sometimes we will do jumps for an entire routine music (jump an 8-ct, rest an 8-ct...).
The first couple times we added these in to our practice plan, we spent ALOT of time working on the sync (like 30-40 minutes). But, it paid off in the long run because now we can bust out the exercises in 1-2 tries to get perfect sync and our jumps are looking so much better than in years past.
Hope that helps!