A dry roll is when Link does a roll at the slowest possible speed by not touching the control stick at all. This is done by holding ZL and pressing A with the control stick in the neutral position. Dry roll speed is 20 whereas normal roll speed is 26.
A jumpslash quickspin is a technique that does a significant amount of damage to an enemy and kills most small- or medium-sized ones within roughly 1 second. To perform this technique, do a jumpslash and then spin the control stick in a circular motion while Link is in the air. Pressing B is not required, the spin attack portion should automatically happen once Link is on the ground again. If used correctly, an enemy will get hit by both the jumpslash and the quickspin portions of the attack. If both portions hit, 6 damage will get dealt the enemy (12 if you're using the Master Sword and 24 if you're using the Master Sword with Elixir Soup). What's strange about this is that a normal jumpslash and a normal quickspin only do 2 damage each (with the Hero's Sword) so the fact that both combined do 6 is wacky. Note that if you are too close to an enemy and attempt this technique, it's likely that the enemy will only get hit by the jumpslash portion. Make sure you have enough distance between you and the enemy before performing it.
If you've watched a speedrun of TWW or TWWHD you may have noticed times when, after rolling off of a ledge, Link won't jump, but will instead hang or simply fall instead. This is achieved by letting go of the control stick before Link makes it to the ledge and is commonly used to setup Ledge Clipping in a quick manner by ledge hanging off of the ledge used to clip.
If Link is facing a flat wall and is right up against it, you can use ZL to target up against it and obtain an angle perpendicular to the plane of the wall. This will usually take at least two separate targets and may sometimes require shifting to a slightly different part of the wall.
While more of a game mechanic than a technique, it should be noted that if Link does not have an item in his hand and you are not currently targeting and press B, Link will simply draw his sword. However, if Link is passively holding an item in his hand (Leaf, Bow, Hookshot, etc.) OR if you're targeting with ZL (regardless of if there's an item in his hand) and you attempt to draw your sword, you will do a slash instead of just pulling your sword.
Much like the last technique described, if Link does not have an item in his hand and you press ZR, he will duck down and begin to crawl if you move the control stick. However, if you are holding an item in your hand (including the sword) OR if you're targeting with ZL (regardless of if there's an item in his hand) and press ZR, then Link will put his shield in front of him. An example of when new runners can get confused by this is when performing Helmaroc Skip. After doing the walk clip portion of the trick and needing to crawl under the arena's spikes, many new runners will shield instead of crawling because they do not realize that they still have the Wind Waker in Link's hands and that they need to put it away.
In TWWHD some enemies can be hit twice using a single stab attack (and ONLY a stab attack, other sword attacks will not double hit). This is done if Link is very close to the enemy he stabs and becomes easier when the Master Sword is obtained as its hitbox is longer than that of the Hero's Sword.
Oftentimes in a speedrun, Link will run through doors that get barred or locked behind him, which he then turns back to look at. It is possible to cancel this animation and save a second by pulling out a bomb right before opening any door that leads into this animation.
By putting away the sail and then taking it out again immediately after, you can get a small speed boost. By doing it repeatedly, you can save around 3s per quadrant. If you have the Swift Sail, then mashing A in order to put it away and then pull it again repeatedly is the fastest way to sail through the ocean (swift sail pumping).
If you sail with the Swift Sail near an island, the game will make you sail at normal sail speed. This can be avoided by taking out the wind waker while having the Swift Sail out and immediately cancelling it (within a few frames). This is especially useful in 100% speedruns in order to sail faster inside reefs.
At very high speeds in the water, it is possible to begin charging a superswim by simply holding Up on the left control stick IF the free-cam is not active. This will allow Link to effectively stall in place and can be used to prevent splooshing on certain islands that need more time to load the water in their quadrants. This can also give smaller islands a chance to load so that Link does not swim through their facades.
If you need to kill your superswim speed at any island, this can be done by holding ZL to target and then holding the direction which will make Link go backward (usually Down) on the left control stick. This will set Link's speed value to 0.
Note: Doing this on land will not work. On land, it will simply make Link's speed positive instead of negative.