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.
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.
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.