When you are using your Deku leaf to glide, it is a good idea to make sure you have the wind blowing the right direction. If you try to glide into the wind you do't really go anywhere and you lose height.
If you catch a fairy and put it into a bottle, then when you run out of health and are supposed to die, you will be revived by the fairy and not have to start over from the beginning of the area you are in.
If you shoot an ice arrow at water (such as out at sea) you can make a large clump of ice crystals temporarily appear for a short time.
Once you have collected the light arrows then you can go up to an enemy such as a darknut (knight with the huge sword and lots of armor) for example and all you have to do is shoot one light arrow at them, and they will instantly die. This saves a lot of time when you are making your way through rooms with several tough enemies later on in the game.