I've had this game for a while now, but I'm stuck at the part after you beat the East Palace. I've got that mirror now, but the problem is...I don't know what to do.
Go to Death Mountain. And lift one of those rocks at the very top. Under the rock is a warp to the Dark World. Then use the mirror where spectacle rock would be. You'll then be on top of Spectacle rock in the Light World. Just go up and jump off Spectacle rock, and you can now go to the Tower of Hera.