There are many ways to clip in Ocarina of Time. Clipping allows one to escape the normal playing bounds of the game, which can lead to some major breaks.
For nearly any angle less than 90 degrees, a jumpslash will be able to push you through one side of the wall. For angles a jumpslash can't get through, a superslide usually can. Superslides can also sometimes get through 90 degree angles.
There are some specific objects that you can use to clip. Specifically, the blocks you can push, even though they create a 90 degree angle, can be clipped through. This is particularly useful in the Fire Temple. Additionally, you can use an armos that you push around to clip as well. This is useful for a Trials Skip. There are also objects, like the hammer blocks in the fire temple you can clip through as well.
Get near a wall and a hookshot-able object (a torch, freezard, iron knuckle, likelike, etc.) close to the wall. Pull out your hookshot and press Z to go to 3rd person. Move sideways towards the hookshot-able object so that you are being sqeezed between it and the wall, then use the hookshot and you should go through the wall.
As child link, when you grab a climbable wall from air, link will clip slightly inside the vines/gate for a few frames. If you get hit during these few frames, you will completely clip through the wall. This does not work on ladders.
While letting go of a vine, press down then up. This will cancel the lag and allow you to regrab faster. Also, you can do it to skip a rung at the top of a climbable wall, and can use it to do wallclipping with bombchus easier, and without needing to fall an unnecessary distance.
It is possible as an adult to use the hookshot and shoot across the top of a ladder. If done correctly you will grab the top of the ledge inside of the ladder. From there you can release the ledge by pressing A and then quickly pressing B to jumpslash and get out of bounds.
With the third thrust of either the Giant's Knife (can be broken too) or the Biggoron Sword, it is possible to clip through specific areas in the game. Typically the hover boots are used as well, so that once you clip out of bounds you have time to get back inside where you are trying to go.