Left-handed Link
In the other Zelda games Link is right handed. In this game, he is left-handed except when facing east. 

Invisible Bed Maker
At the very beginning of the game when Link is in bed and the man says that he is going out and Link is supposed to stay home, get out of bed. The bed will be messed up. Go outside and then back in. The bed will mysteriously be made, but no one was in the house after Link left. 

Invisible sword
Select the flute, then hold B. When the duck is touching you, release B. There will be a swirling yellow light where you were standing. 

Easy Ice Palace
Before you go into Ice Palace, go to Misery Mire and get the Cane -- you can also complete that area if desired. Then, enter the Ice Palace and go to the room where you have to push the block onto the switch to enter the door.. You now can just use the cane instead of doing that. 

More Keys
On Gannon's Tower go to the far left set of stairs. Get the key and go back up, but do not open the door. Go to the far right set of stairs, and you will have an extra key. Do not open the first locked door you see. 

Eternal Torch
Enter a room with four torches in a dungeon. Light three of them, then immediately when the second one is going out, light the fourth one. If timed correctly, the second torch will never go out.