Hanging something really heavy, like a mirror, may seem more difficult than hanging a small painting. With the right anchors, though, it's pretty simple. Here's a tip to keep your newly-hung mirror from going askew.
Before hanging anything, you need to determine what type of wall you have. From plaster and lathe to brick or drywall, each type of wall requires a different set of anchors. This handy graphic serves as a guide to matching wall anchors to wall surfaces.
To keep your heavy mirror level on the wall, use two anchors. Place a scrap piece of wood (20-30cm depending on the size of your mirror) underneath the taut hanging wire. Then measure from the wire to the top of the mirror frame. This measurement will assist in the placement of your mirror on the wall. Mark the end points of the scrap wood on the wall and that is where the bottom of the hook should be placed.
Watch the video above to see this DIY tip in action.
How to Hang a Heavy Mirror [This Old House (YouTube)]