The Orca fight contains a few tricks that will speed it up by a few seconds.
During the first phase of his training, you will need to perform 3 combos (the normal combo, the holding target combo and the stab combo). However, instead of performing these combos normally, you can instead start holding back on your control stick before your 3rd hit, and holding forward on the control stick before the 4th hit. This will make you do a combo that ends with a spin attack instead, which is faster.
Then, Orca will want to you to perform a spin attack. Perform a quickspin by doing a full circle on your control stick before pressing b, which is faster than doing a spin attack by holding the b button.
Then comes the parry attack. Target Orca and wait until the arrow above his head goes up for its 4th time. Then press A to parry him. If you parry Orca on either the first or the second possible frame, his second parry will come instantly after the first one, saving 4 seconds.
Finally you will need to perform two jumpslashes. You can perform a very slightly faster jumpslash on the 2nd one by sidehopping and pressing b to do a fast mid-air jumpslash.
If you don't have a sword, then there will be an invisible wall behind the trees preventing you from accessing the Forest of Fairies early. It is however still possible to enter FoF without a sword using one of the following tricks.
The invisible wall behind the trees doesn't extend on the ledge on the left side. This means that you can enter FoF early if you can just get onto that ledge. This is very easy with the deku leaf: simply jump onto the roof of Mesa's house and leaf to the ledge.
There is a simple way of getting door cancel on Outset. Get dry storage and then activate Sturgeon's text (it's the old man above Orca's house that teaches you targetting). Then open the door leading to Orca's house. This will bring up Sturgeon's text. Mash through it to cancel out of opening the door. You know have door cancel. With door cancel, the invisible wall poses no issues anymore, but you will have to manuever up the island in the dark.
The video below uses a cheat in order to remove the fadeout, which helps with understanding what is happening in the video above.
The invisible wall behind the trees when you don't have a sword doesn't extend onto the ledge on the left side. By building up speed with a superswim, it is possible to slide up the mountain to the invisible wall and then jump and land onto that ledge and avoid the invisible wall alltogether.
Entering FoF early can be very important depending on the route. If you don't save Tetra in the forest normally, by performing Outset Escape to skip it, entering the forest later in the game can have unpleasant results. If you haven't saved Tetra, and if you enter FoF either during night, or after FF1, then the game will simply crash no matter what, which can prevent you from ever obtaining the last wallet upgrade. If you wish on not saving Tetra in a 100% speedrun, then you must obtain that wallet upgrade before beating FF1 and during the day.
Normally, entering the Fairy Fountain in FoF requires using bombs or power bracelets to remove the boulder preventing you its access. However, it is possible to get in early with the leaf by doing a precise roll clip, and leafing under the boulder into the loading zone.
If you got the Wind Waker early, you can do a few interesting strats inside the forest. First, you can get dry storage before activating the bokoblin fight, which allows you to hit the bokoblins faster. Get Storage again and then defeat the bokoblin. This will allow you to save and quit during the Saving Tetra Cutscene, skipping it. This counts as saving Tetra and will allow you to obtain the wallet with no risk of crashing later.
In order to obtain Nayru's Pearl, you must first activate Endless Night by going to Greatfish. Then you need to break the wall on Outset. The cutscene that follows breaking the wall will load you into the cutscene where you will obtain Nayru's Pearl. The following tricks are useful in order to obtain Nayru's Pearl without having to sail and shoot bombs from KoRL.
More Info to come
You can break the wall on Outset without KoRL using Door Cancel. Using precise movement in the dark, it is possible to get up the island and then stand on one of the sides of the wall you need to break. From there you can just throw bombs to break all 3 parts of the wall and get Nayru's Pearl without having to sail.
Since both Outset Escape and superswimming are possible, it is possible to avoid most uses of KoRL during early game. KoRL only appears on the overworld once you've beaten Forsaken Fortress 1, and so this trick can be used in order to unlock access to TotG before beating FF1.
Because the last savewarp flag is set upon entering KoRL, this also skips setting that saveflag when obtaining Nayru's Pearl. By beating TotG before beating FF1, you can then savewarp in Hyrule 1 to get back to the overworld very fast. This is usually referred to as the Hyrule 1 Savewarp Escape. Since picking up the Master Sword in the MS Chamber is a required trigger to break the Hyrule Barrier, savewarp after watching the Master Sword Cutscene to escape Hyrule 1 without dead-ending your file.
Instead of having to pickup the large pig, and having to carry slowly across the island to the black soil containing the heart piece, it is possible to throw the pig the entire distance. To do this, pick up the pig and place it between the wall of the pin and the guy. (It should be noted that this can only be done during the day, as the guy is not there at night.) Go over to pickup the pig again and make sure that the action on the A button is rapidly flashing "Lift". You will notice that you are not holding it directly over your head. Now get out of the pin and throw the pig towards the soil. You will notice that now you can toss the pig the entire span of the water.
By getting damaged by the fire and then quickly using the Hookshot on the torch, you can enter the hole before the temporary damage invincibility wears off. This trick can be performed on floors 21-29 as well as any other floors with torches. The Iron Boots can also be used in order to minimize the distance of the knockback from the fire so that it is easier to enter the hole with the Hookshot.
You can reload the 30th floor of the Savage Labyrinth by picking up the rupees in the pots, storing the chest containing the Triforce Chart, and getting crushed by a pillar. This reloads the area and allows you to get the rupees in the pots again.