See Bottom of the Well Early for more info.
See Early Bombchus for more info.
You can grab the gold skulltula in the room behind golden bars without the boomerang. First, jumpslash it for the kill (you can stand on the chest to make this easier). Then, line yourself up in between the Like Like and the token, and let the Like Like eat you. If angled correctly, you will be tossed into the token and collect it.
As the boomerang returns to you, it can pass through any solid object. You can use this to obtain the small key in the coffin room without lighting the torches. The boomerang with go through anything on the way back so if you throw it past the coffin, you can get the small key from within without lighting the torches.