Here are three different methods:
1. Go to Mystery Mire in the darkworld, and then go to the path that leads to the ether symbol/dungeon entrance. Stand near the bottom of the lilly pad that's a little off the concrete. Teleport. Now, go to the tablet and use the Book of Mudora. The stone should move over your portal. Go into the dungeon and come back out, and you will be stuck. Use the ocarina or go through the dungeon and jump off the ledge to get out.
2. Go one screen south of Kakariko village, to the place where the angry brothers, the library, and the shooting gallery are. Jump down the first ledge, and stand anywhere on the ladder. Now warp, and move up or down, depending on how far you are. And now, no matter how much it looks like it, you can't get to it again if you did the glitch correctly.
3. Go to the place where the first medallion/crystal is, and go near the bottom left hand corner. It's hard to explain, so where you enter the area, go up the dash right until you hit some trees. Now go below and to the right of where the trees are close together. Try to aim to hit the upper ledge on the dot. If done right, move up and you won't be able to get back to the mirror.
Submitted by: Thor