Once you get access to Termina Field, it's possible to do some sequence breaking. Walk up to the northern passage blocked by ice, Z-target the icicle from a distance, and jump to the right. If done correctly, Link will walk on the rocky outcropping adjacent to the ice. This gives you access to the Mountain Village, Goron Mask, and the Lens of Truth without having the Hero's Bow.Once you have the Goron Mask, head for the Great Bay. There's a fence blocking the path that normally requires Epona to get over, but you can use boost damage instead. Lure a ChuChu from the nearby patch of grass in Termina Field to the fence. Switch to Goron form and use his ground pound jump. If timed correctly, the ChuChu will hit you at the apex of the jump, triggering Link's falling/damage animation and giving you enough height to clear the fence. You'll get the Zora Mask shortly afterward. If you're stocked up on Deku Nuts, you can also go to the Pirates' Fortress and obtain the Hookshot; use the nuts to stun the guards, and use Zora Link's boomerang fins to trigger the beehive and clear the treasure room. If you have some spare Deku Sticks and Bombs afterward, you'll have everything needed to complete the Oceanside Spider House, which nets you the Giant Wallet much earlier than normal. Thus you have access to all three major transformations in the game and a few great items before even setting foot in a temple.
You can upgrade the Bomb Bag's capacity by performing a couple of tasks.
After you've regained Link's Hylian form, go to the top of the East Clock Town stairs and do a rolling jump over gap between buildings at the Eastern Gate. Continue jumping close to the wall, using the decorative targets above the Honey & Darling's Shop as makeshift platforms. Continue walking behind the Town Shooting Gallery sign until you reach a trunk containing a Silver Rupee. This treasure can be claimed once per time loop. Also, the targets above the Honey & Darling's Shop will produce several Green Rupees if you shoot them with your items or Deku Link's bubbles. This second trick resets every time the East Clock Town screen loads.
After cutting a wooden sign to pieces, play the Song of Healing. The sign will magically repair itself.
In the upstairs room at Mama's House in Romani Ranch, hiding in a corner behind Romani's bed, there is a toy horse that looks like Ganondorf's horse from Ocarina of Time. Also, on the mantle above the bed is a toy horse that looks like adult Epona.