Hint #1
In the beginning of the game you are on destiny islands. When you see a thunder storm and run outside there will be heartless. Do not try to attack them they will not go away. (your sword is too weak) Instead go in the shack and across the bridge there you will recieve your keyblade. (this will help you not lose your life so you can defeat the heartless later and take on the big black thing)

Hint #2
With the white mushrooms, in order to get the spell arts, you must cast a certain magic 3 times with the same magic however they do not have to be in a row so wait for the mushrooms to move into the same pose.

Poses/Magic:
Shivering/Fire magic
Squatting or sweating/Blizzard magic
Light above head/Thunder magic
Spins/Aero magic
Floats off the ground/Gravity magic
Falls on the ground/Cure magic
Stops completely/Stop magic

Hint #3
If you need mystery goo and your not very good with the rare truffles (which you have to knock into the air) the white mushrooms drop mystery goo along with the spell arts.

Hint #4
The enemies in the colosseum will not drop items so don't bother trying

Hint #5
During the fight with Riku 2 at Hollow Bastion, use the Olympia keyblade for some reason this makes the figt easier

Hint #6
While fighting Cerberus don't take him head on its suicide instead lock on to a side head and show him what the keyblade's made for

Hint #7
While fighting the ice titan you must hit the shards he spits at you back at him however if you use aero magic the chunks get huge and impossible to hit back at him

Hint #8
When you fight the dragon in hollow bastion, there is a root along the wall that you can hide behind, it will block you from almost all of the dragons attacks, so let your party members do all the work and then just come back to finish it off.

Hint #9
After you beat hollow bastian then you can fight the secret bosses. One of these is in agrabah. Go to aladdins house and the carpet should be dancing around, talk to him and when they ask you a question say yes. Then you should have to fight a secret boss. Once you start fighting him, you will not be able to use magic. So you have to destroy the two balls in his hand. After you destroy the two balls, you can hurt him. Then he will jump back up and you can use magic again. He will have a shield around him that you must destroy. The best way to destroy it is to run up to him and use thundera (or thundaga) on him. After you destroy his shield you have to reapeat it, except this time he will fly up in the air and spin around. The only way to dodge this is to dodge roll under him. Keep repeating this and you should win.

Hint #10
Summon Tinker Bell in your fights. You can get her after beating Captain Hook, then sealing the keyhole at Big Ben. She always heals the party, and so you never die.