When first flying to Faron, it is possible to skip the text where Fi tells you about the map. By diving off your loftwing at a high enough height before the text triggers, you can skydive over to the Faron entrance.
If you skip the adventure pouch (in a Harp run, for example), the dive button for your loftwing will not be unlocked, and thus you will be unable to do this trick.
While there are many solutions, the fastest solution is as follows:
By sidehopping as you complete the Isle of Songs Puzzle, you can skip the cutscene that plays when you solve the puzzle, thereby saving 3-4 seconds.
With the discovery of Reverse BiTMagic, it became possible to beat dungeons out of order, and thus came the question of what are actually the requirements to learn each song. When you skyward strike the goddess crest, the cutscene that you will watch depends sorely on what sword you have in your inventory: with the Goddess Sword you will learn Farore's Courage, with the Goddess Longsword you will learn Nayru's Wisdom, with the Goddess White Sword you will learn Din's Power. If you have the Practice Sword, the Master Sword or the True Master Sword, you will not learn any song.
The route below is the fastest known route for spiral charge, able to get a time of 76 seconds remaining.
The Bug Wrangler mode of Bug Heaven is required during 100% runs. The following route, if done perfectly, can get times under 50 seconds, and can be consistently done in under a minute.
To increase your odds in the Fun Fun Island minigame, use the following strategy. As you pass through the final ring, find your target spot on the circle below you. Treating the board as a clock, aim for the spot three hours later on a clock. Then make adjustments as you come in to land.
For example: as you pass through the last ring, the 50 rupee space is at the top of the circle (12 o'clock). Aim for the right side of the circle (3 o'clock), and then make adjustments from there.
For the adjustments, when you are skydiving the more you move left and right, the faster you will fall. So if you have to move a lot to reach your target area, you won't have to make many adjustments. However, if you don't have to move at all to reach your target, then you'll have to make more adjustments as you fall.
If you have the ability to dive during the loftwing tutorial, it is possible to dive towards a zipper, and call your loftwing to make it enter it. For some reason, the speed boost from the zipper will never wear off. Also, the longer you are stuck inside the zipper the more speed you will build.
It is possible to enter the Isle of Songs without solving the puzzle at all. Land on the Isle and push the spindle so that the outermost platform moves once. Now dive off the island and call your loftwing. Quickly land on the middle platform, then as the outer platform rotates around, run onto it. You can then roll into the Isle of Songs as the platform passes the crawlspace.
This trick is very precise and slow to setup, making it actually slower to do in full game runs.
While it is slower than the usual Early Life Tree Seedling on Skyloft, it is interesting to note that you can use Reverse BiTMagic to make the Life Tree Seedling appear in the Lumpy Pumpkin island pumpkin patch. This is not a regular scene flag RBM as the life tree seedling is a temporary scene flag (temporary flag 2x20) but the concept is the exact same.
To do this, save your file in the Sky (either at the Lumpy Pumpkin statue or inside Isle of Songs). Activate BiT and maneuver near the Owl Statue that opens Sky Keep in BiT Skyloft. Start your file then bonk the tree left of the Owl Statue.
The next step is to commit the flag and look at the pumpkin patch to get a Fi Text. You can now dig up the life tree seedling.