[1:33] Mistake #2: Do not side step the rotating kick (= kicking leg) too much in the initial step to avoid telegraphing; just pivot it in place for about 45 degrees till your foot gets horizontal.
[3:06] Mistake #3: Do not start rotating your head until the pivoting phase above is over.
[3:45] Mistake #4: (possibly most important) Do not lift up the swinging leg (= non kicking leg) in preparation of the jump; instead, just rotate it outward and then shoot it diagonally upward.
[4:25] Mistake #5: Do not jump until the swinging leg faces your opponent.
[4:50] Mistake #6: (not sure about this) When you jump, give your swinging leg a twist.
[5:38] Mistake #7: (not sure about this) Either land while facing your opponent or keep turning further till you face your opponent [7:13]
Tutorial by the same guy
Good application of TKD kicks, including the tornado kick
3:29 Clips from the same bout above from a different angle