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 L and pressing A with the control stick in the neutral position. While a dry roll goes almost nowhere, normal roll speed is 26.
Because of the dry rolling mechanic, you will always want to reach full walking speed before starting to roll in order to have fast rolls. Dry Rolls can be useful to setup precise tricks, but that is all.
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 L 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 L (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. Most of the time, this is the reason why Link slashes his sword after a failed dry storage, it is because you have the wind waker in hand and pressed B one time too many.
Much like the last technique described, if Link does not have an item in his hand and you press R, 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 L (regardless of if there's an item in his hand) and press R, then Link will put his shield in front of him.
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 a lot of time over long sailing sections.