Using the Infinite Sword Glitch (ISG) and backflipping into shieldable damage, Link can literally hover in the air and reach distances once thought impossible to reach. This is easily one of the most useful techniques in the game, if not the entire series (although it's even more useful in Majora's Mask).
To hover you need damage to hit your shield. Bombs and bombchus are the most commonly used methods of damage, but most enemy damage will do. To start the hover there is a prerequisite height that must be reached or else you will fall back to the ground. Starting a hover from one bomb on flat ground is not high enough.
When ISG is activated, it will prevent you from walking/running off edges; in fact, you can even get stuck at the very end of an edge if you keep pressing against it. This is the key idea behind bomb-hovering and other ISG related hovering techniques. When you shield damage in the air you are able to stick, as if grounded. And once stuck, ISG will not allow you to move from that spot because you can't walk off edges normally and there is no ground you can walk on since you are in the air.
OoT hovering methods vary greatly from its MM counterparts because of their different explosion mechanics. OoT's bombs are animated, meaning that the blast radius will start small and will expand every frame until it reaches full size. MM's bombs hit in the full range of the explosion for the duration of the blast, with no spreading or variation in range. It's because of this pivotal difference that many techniques have been developed for OoT in order to be able to hover in the first place.
Because of the slowly expanding blast radius, sidehops and backflips can cause you to move away from the explosion too quickly. To compensate for this, a variety of techniques have been developed, many of which involve using an item to slow Link's acceleration. This brings us to the hoverboots, which cause Link's backflip to gain less distance, making bomb and bombchu hovering much easier than if you weren't wearing them. Another way to make bomb hovering easier is to hover while against a wall. The wall will shorten Link's backflip distance.
The easiest way to bomb hover is to get ISG and put Link's back against a ledge or small drop while wearing the hover boots. If you lack hoverboots, the alternative is to make sure there's a wall or object close behind Link's backside to shorten his backflip distance. Either way, when you pull out a bomb you'll notice Link's breathing animation will reset. Right at the moment when Link's second exhale begins, press and hold the shield button to drop the bomb, immediately followed by a backflip. Timed correctly, you should now be suspended in midair a bit farther back and higher than you were previously. You no longer need to hold the Z button and you can repeat the same bomb hovering process as many times as you like.
NOTE: Hovering with the hoverboots on is much more forgiving. The slower acceleration gives a bigger window of opportunity for the backflip, allowing more room for adjusting the height or distance you gain from each hover. With Kokiri Boot hovering, the timing is much tighter, which allows a smaller range of height/distance control.
The staircase hover allows you to get off of flat ground, when no ledges or slopes are present. To do it, place two bombs about one sidehop apart, while dropping the second bomb a second after the first. The easiest way is to hold Z, shield drop the 1st bomb, backwalk just outside the reach of the 1st bomb's explosion range, and shield drop a second bomb. Then just run forwards back in front of the 1st bomb and time the backflip so that you are over it when it explodes. You should stick in the air, then backflip again before you fall back down the the ground (because you aren't high enough) and, if timed properly, you should stick the hover over the 2nd bomb and be high enough to hover without falling back down. It seems hard at first but before long you'll use it for starting every hover on flat ground, which is quite a useful technique to have at your disposal.
Adult Link has the luxury of hover boots which allows for the easy hovering due to their slow acceleration. A backflip with hover boots will be short enough for a Bombchu to hit your shield, if you don't wait too long. Just backflip then shield drop a Bombchu, holding the shield button until the explosion stops. To gain more height than distance, pull out the Bombchu first, then shield drop it and backflip at the same time. You can also sidehop hover with hover boots, but you need to wait about a full second after sidehopping before shielding the bomb to make sure it doesn't damage you.
This is a very difficult method of bomb hovering. You'll need to backflip a bit later than you would with the Breathing Method. The timing is very strict (only a couple of frames of leeway), since your backflip will gain full distance.
If you are Young Link and the above method is a bit too hard, you have the option to use Slingshot Hovering in order to halt link's momentum. Pull your Slingshot out and draw it back (a seed is not required) and backflip, then fire the Slingshot. Timing is everything: The faster you fire the seed, the more height you will get whereas the longer you wait, the more distance you will get. After you have fired the seed to stop your horizontal movement, shield drop a chu and then continue holding your shield. The chu should hit your shield easily and you will stick the hover.
As Adult Link, you can replace the slingshot with the bow or hookshot to get the same effect.
Using the hookshot/longshot's aiming system in conjunction with a backflip, you can travel a large distance during bombchu hovering. Get ISG and back against a ledge. Hold Z and pull out your hookshot, now aim directly upwards until the hookshot's red dot stop moving. Press A to do a backflip and then immediately shield a Bombchu.
NOTE: Contortion hovering with not work if too many objects are loaded near Link. It also only works with the Kokiri Boots.
While hovering in the air, hold the control stick at a slight downward angle, just enough so that Link tries to backwalk slowly but the A button still says "attack". If you press A you will do a sideroll, and if you hold it down and at an angle to the left or right you can control the direction he faces with the roll. If you backflip when coming up from a sideroll, when timed properly, it will do a sideflip, a sideways backflip. This shortens the backflip's length by altering its trajectory, so that pulling out a chu and shield dropping it allows it to still hit your shield; unlike a normal backflip where shield dropping it won't hit your shield. Sometimes a sideflip will instead come out to be a backwards sidehop which doesn't help at all. This method is pretty difficult and is generally only used for hover boots skip purposes because there are others ways to shorten backflips. However, it does cover a lot of horizontal distance per flip. The order of this trick is where you sideroll, sideflip, and then very quickly shield drop the bombchu after the sideflip. Precision in your timing of the shield drop is necessary.
While in the air, hold the control stick forward, then tilt it either slightly right or left. Link will slowly walk in that direction, rather than go into his sidewalk animation. If you pull out a bombchu and then backflip from this position, Link's shield will just touch the edge of the explosion radius. It is also possible to get this to work with a sidehop as well.
On the N64, if you shield drop a Bombchu into an Out of Bounds void it will freeze the game. In the GCN versions, this will instead create a double explosion large enough to hit your Shield, even if you do a normal Backflip, removing the need for the above methods. You can even Sidehop Hover as a child, thanks to the bigger explosion. On the VC version, there is neither a freeze, nor a bigger explosion radius.
NOTE: If there is another bombchu running in bounds, Shield Dropping a Bombchu Out of Bounds will freeze both the GC and VC versions. It is currently unknown why this happens.
If you try hovering over a surface that would make you slide off it, you will become stuck in place. You cannot backflip or sidehop, and only occasionally will you be able to roll. To get down, you'll need to either draw your sword or use an explosive to end the hover. However, if you have the Down A glitch activated while hovering this will not happen because Down A can walk on slippery slopes normally.
Normally when hovering, pressing Z will lock your angle, preventing you from re-adjusting your hover mid-air. If you target something (an enemy, bombchus, etc.) while hovering and untarget, it will unlock your angle (and re-adjust the camera) allowing you to rotate freely. To be able to change which direction you can backflip or sidehop, you'll have to target once you have the angle you need.
If you have the Down A glitch activated, you can change your angle mid hover without the need of a target-able object. This type of hovering works best when Swordless because the Down A glitch disables your buttons, whereas being swordless allows you to use them again. Because of the requirements its rarely used, but its very fun to mess around with.
Like the Sideflip Hover method, this trick utilizes siderolling to alter the trajectory of the backflip so that it contacts the shield. Normally because of our jumping options, we are limited in the direction we travel while hovering to the backwards or back-diagonal directions. This technique allows us to travel forwards with our hover, which is of great use depending on the location of the hover. It is preformed by doing a sideways roll, and then near the end of it, doing an additional sideways roll in the same direction. This alters the angle Link is facing so that it is nearly facing backwards. Press forward and A and you will have executed the forward backflip.
You cannot hover while Nayru's Love is active. When your shield contacts an explosion in mid-air while it's active, it'll result in an aerial superslide instead, and the hover will not stick.