why do u want to jump in the air? ^^
just try to find youre own move, click randomly joints, try to prepare to kick or punch your opponent, try to block a maybe comming punch or kick with the same move, or also u can try to counter the enemy move... there are much options but the best way is to find your own move. u dont have to push up in the air. in some mods is it bad to come in the air (like aikido) try to practice in singleplayer against uke, find YOUR move.
Judo is a mod that is mostly luck. But here is something to remember about kicks.
1: Get momentum. This means if you kick with your right foot turn right and use your arms legs and body to turn into it.
2: Use a back up move. Meaning if your leg misses or does not do much damage then try to throw your opponent to the ground. remember still use momentum.
Keep practicing. You will get better.