Gauge the size and weight of the mirror. If your mirror is particularly heavy, you can hold it while you stand on a scale to see how much it weighs.
Get two saw tooth picture hooks that are appropriate for the size and weight of the mirror. Some of these saw tooth hooks can hold 50 pounds and more. Even if you are tempted to only buy one saw tooth picture hook, always go with two for added support.
Locate wall space. Find a safe area at the height you want and hold up the mirror, marking the top border with a fine pencil line. Use a stud finder to locate beams into which the screws can be inserted and adjust the mirror's position accordingly.
Attach the saw tooth picture hooks to the mirror. Using a durable glue, attach the two saw tooth picture hooks to the back of the mirror, about one-third of the way down from the top.
Align the mirror with the border you drew against the wall, once the glue is dry, facing the wall. You can draw two dots at on either side of the mirror at the same height as the hooks. Also, draw two dots at the top of the mirror to indicate their position.
Connect the dots. Use a ruler to connect each top dot to each side dot to indicate where you should nail the nail into the wall. Screw your two screws into the wall.
Hang the mirror. Carefully slide the saw tooth picture hooks onto the nails. The saw tooth hooks allow you to slightly reposition the mirror so it hangs straight.