When fighting the last form of Ganondorf, you don't have to go head on with this powerful villain. There is an easier way, and this is how the trick works:
- Put the Fishing Rod in one of your item slots.
- Get up close to Ganondorf (you may need to dodge his attacks first) and throw the Fishing Rod close to the his head. He'll get distracted by turning his head to where you threw the Fishing Rod. With him distracted and vulnerable, take out your Master Sword and strike him until he counters or blocks your attacks.
- Do this a few times to defeat him.
Easy Access to boss room in Water Temple
If you have the boss key, you don't have to hit the last switch to raise the water level to let you swim into the pivot. Instead, make sure the rotating staircase is straight below you, then you can clawshot up to the chandelier, and jump to a place on the staircase so you land next to a decorative piece. If executed correctly, you should stop and not slide down the railing. Now you should be able to drop down onto the pivot where the boss door is located.