Get the Spring Morning trampoline and train on it. The ninja will jump higher on this trampoline. The Spring Morning trampoline can only be purchased at Level 6 for Coins, otherwise you have to use Gems. Keep training on the First Jumper trampoline and the Punch Bag to get to level 6 and use your Coins rather than wasting the Gems if you can (Reward: 45 XP, 10 Coins)
"Let's see if all that jumping has improved the young ninja's aim"
Complete a session with the Old Rice Sack! This is the same punching bag we've been using so far - just repeat the training as before to complete this task (Reward: 15 XP, 5 Coins)
Hmm, a small improvement. Let us try a static target. Place three Wooden Crates. Do this simply as we did the first time earlier in the game(Reward: 35 XP, 5 Coins)
Tap the Wooden Crates to get the ninja to attack them. Then let him deal with them - ninja style! This one is self explanatory (Reward: 65 XP, 10 Coins)
"It is up to you how to train the ninja - all interactions help him towards his next belt!"
Use your preferred training methods to level up and get your turquoise belt. It will take quite a while and all of the training methods that you have available (Reward: 150 XP, 20 Coins)