Water Scroll: In the 4-Paws island (Chapter5), go through the middle of the island and turn upside. You will fight a monster. When you defeat it, it will hide. Follow it and search for the yellow chest. Enter two key items and use the scroll. You will get a water bending power for Katara (revives your friends in battle).
Earth Scroll: In the Air Temple (Chapter6), go to the south and find the Earthbender. Talk to him and win the challenge. Then, use the scroll as done the last time. You will get a similar move like Haru's Boulder-Kickin', but it will be slower, bigger, and more powerful.
Air Scroll: In the Air Temple (Chapter 6), go west and north after getting out of the temple. When you get there you will have to play ''The 4 Nations Force'' game with the spirit of Gyatso. It does not matter if you give up or lose. You will get an Airbending scroll. Use it to get a tornado-like attack for Aang (you can move it).
This is a tip more than a cheat. To beat the boss (in the cave after you helped haru\'s father beat the machines) use melee attacks because they are more effective. u should be aang, his melee attacks work better than the rest.
On four paws island in the town you will find a little girl, talk to her and see will take Sokka's club and run of with it so you will follow her. Only Sokka does this mission.
Acquire all Set Items through level 3.