Bosses of The Legend of Zelda: Ocarina of Time
The bosses in Ocarina of Time are big and tough, but if you figure out their patterns and expose their weaknesses they become much easier. Here is a guide to help you out:
 Parasitic Armored Arachnid, Gohma
When you run into the boss room, look up and Gohma will appear. To defeat this parasitic armored arachnid you have to first "Z" target her and then paralyze her by shooting her with your slingshot or by throwing Deku Nuts at her. Then when she's stunned run up and slash her with your sword as much as you can before she runs up the wall once again. Repeat this process a few times and kill all of her minions and you should be done with her easily.
Gohma was also a boss in The Legend of Zelda.
 Infernal Dinosaur King, King Dodongo
Walk towards the middle of the room and he'll come right for you. King Dodongo only has two attacks, he can breathe fire and roll around the room. Go to a safe place (Preferably right on the corner of a the lava) where he can't squash you and then run after him, wait for him to try to obliterate you with his fire and then throw either a bomb or bomb flower into his open mouth.
Repeat this process a few times and you will have him defeated.
Dodongo was also a boss in The Legend of Zelda.
 Bio-Electric Anemone, Barinade
This huge jellyfish is a more complex than the last two bosses. First get in close to him and hit his wiggling top tentacle with you newly acquired boomerang. Smaller jellyfish will come out and you can hit them too if you have time (it makes things a lot easier), once you get the chance, throw your boomerang at his body and he'll be temporarily paralyzed.
Go up and attack him with you sword. Like the other two bosses, just repeat this process and you shouldn't have much trouble.
 Evil Spirit from Beyond, Phantom Ganon
This boss has two stages. The first one he'll have a horse and can enter other dimensions. There will be two paintings with an image of Phantom Ganon racing towards you, you have to hope that you're looking at the right one. Shoot him with an arrow and if you have gotten the right one a cloud of purple will appear in the painting and he will shout in pain. After doing this a few times he will come out of his paintings to his second form. This time he is without a horse and wants to play a game of tennis. He will fire large electrically charged balls at you that you must hit back at him till it hits and stuns him. Phantom Ganon will fall to the ground and you can use the Master Sword to cut him up. Do this a few times and you will have beaten the first temple boss.
 Subteranian Lava Dragon, Volvagia
This is the second fire-breathing monster that you will encounter (the first being King Dodongo). He has three main attacks. He will throw a horde of giant rocks at you from above, he can run you over or set you on fire. Sounds fun, doesn't it? If he pokes his head out of one of his burrows, give him a nice thump on the head with your megaton hammer, he will be stunned so you can either continue to wack him with the megaton hammer or use your sword. You have to be pretty patient with Volvagia because it can be a while until you an attack him again. While your waiting just focus on dodging his attacks and you'll get to attack him again. After doing this several times he will have a dramatic death and drop you a nice heart container as well as a warp.
Volvagia is a monster known mostly from Goron legend. Far before Ocarina of Time takes place, a Goron hero used the Megaton Hammer to defeat the beast. Volvagia was reincarnated by Ganondorf in Ocarina of Time, and was used to threaten the Gorons to death. Almost all of the Gorons were imprisoned within the Fire Temple, and would have been fed one by one to the beast had Link not freed them.
 Giant Aquatic Amoeba, Morpha
The Morpha can be a tricky boss if you are not fast on your feet. To start off, get off the platforms and go to the floor surrounding the water area. It will be extremely hard to beat this boss if you do not do this. Make sure you keep a safe distance from the boss. If he catches you with his tentacles it could mess up your next few chances to get a hit on him. With that being said, make sure you have your long shot equipped. "Z" target onto his center and fire away. There's not much you can do to make sure you will catch him with the long shot so just try to fire your long shot at him as much as you can. If you catch him, he'll be helpless and brought right to you by the long shot, hack away at him. Repeat this process and make sure to avoid all of his tentacles and you will have the Water Temple beaten.
Morpha was a monster who was created and put in the Water Temple by Ganondorf. He froze over Zora's domain and the Ice Cavern, imprisoning all of the Zoras until Link slayed him.
 Phantom Shadow Beast, Bongo Bongo
This boss has perhaps the easiest routine but he is one of the hardest. You're going to need two things equipped just to survive, these are the Hover Boots and the Lens of Truth. If you're not wearing the Hover Boots you'll be repeatedly thrown into the air by his bouncing and if you're not using the Lens of Truth you will not be able to see him. To defeat this monster of a boss, first shoot him with your arrows on both of his hands, he'll come down at you, so make sure you have your sword out. Hit him in the eye with your sword and he'll be hurt. It sounds easy, but shooting him in the hand can be rather frustrating. Like all the other bosses, just repeat this process and you'll be done.
 Sorceress Sisters, Twinrova
That's right, this boss is actually two bosses. They are elemental sisters, one is fire and the other is ice. Make sure you have your shiny mirror shield out, if the ice one shoots ice at you; deflect it towards the fire one, if the fire one discharges flames towards you reflect it towards the ice one. After doing this a few times they will realize their plan isn't working and they will combine. What you need to do now is reflect back the same element three times in a row. So either fire-fire-fire or ice-ice-ice. Once you do that they will retreat and you can hit them, make sure your wearing your hover boots and chase them down and give them a nice greeting with your sword. After you do this a few times you'll have the sisters beaten and the only boss left will be Ganondorf himself.
 Great King of Evil, Ganondorf
This fight is pretty basic, and it's a lot like the Fight you had with Phantom Ganon in the Forest Temple. But what makes this different that Phantom Ganon is that you cannot 'Z' target him with Navi, so make sure you aim carefully. To defeat him, go to the outer part of the stage and wait for Ganondorf to fire large glowing balls at you, hit them back with your sword until he is stunned, then fire a light arrow at him. He'll fall down and then you can run up to him and give him a good beating with your sword. After repeating this a few times he'll be dead.
Ganondorf is back, but this time he is in his true form... a giant, sword wielding pig. Don't worry, it looks a lot cooler than it sounds. This battle is going to require a lot of magic, because I highly recommend that you equip Nayru's Love for this battle. If you ever need more magic, go over to the destroyed castle walls and have Ganon hit them with his tail, sometimes magic refills will appear. Now that we've gotten all that out of the way, onto killing him. You're going to be without your Master Sword for the first portion of the battle, so have the Biggoron's Sword or Megaton Hammer Equipped. But you can't use those until he's stunned, so fire a light arrow in between his eyes (Navi can help you with this again). After bringing him to the ground, get to his large, glowing tail and attack him as much as you can. After doing this a few times, you'll be able to retrieve the Master Sword. Equip it and do the same thing as you were doing before until Zelda tells you to deliver the final blow while she holds him down. Deliver the final blow and you've beaten the game!