Hi, and welcome to Hyrule. I got Ocarina of Time the week it came out last Thanksgiving and I have now finished it three times, once properly, once to find every Piece of Heart, and once just because I missed it. This walkthrough is what I wish I'd had the first time, when I spent two full evenings stuck in the Water Temple and nearly threw the controller into the fish tank.

I've tried to tell you where to go and what you need without playing the game for you. Where there's a puzzle I think you'll enjoy figuring out yourself, I say so and you can skip my hint.

Part One: Young Link
  Kokiri Forest · Inside the Deku Tree · Hyrule Castle · Death Mountain and Dodongo's Cavern · Zora's Domain and Jabu-Jabu's Belly · The Door of Time

Part Two: Seven Years Later
  The Hookshot · Forest Temple · Fire Temple · Ice Cavern · Water Temple · Biggoron's Sword

Part Three: Shadow, Spirit and the End
  Coming soon! I have the notes in a spiral notebook. I just have to type them.

• Use Z-targeting for everything. Hold Z to lock on to an enemy. Link will circle it and block properly. Half the fights in the game are easy with it and hard without it.
• Talk to Navi. When she flashes green, press up on the C-buttons. She's annoying but she's usually right.
• Break every pot and cut every bush. Rupees, hearts, arrows, Deku seeds.
• Get bottles. There are four in the game. A bottled fairy saves your life automatically when you run out of hearts.
• Hearts: you start with 3. There are 8 Heart Containers from bosses and 36 Pieces of Heart (four make a heart), so the most you can have is 20.
• Gold Skulltulas: there are 100. Turn in their tokens at the House of Skulltula in Kakariko Village. You get the bigger wallet at 10 and a Piece of Heart at 50.