Way to hang a mirror on the surface of the drywall will depend on how much it weighs. Light mirror can be attached with liquid nails or double-sided tape, but the design is heavier than 20 kilograms, will create too much load, so you should attach them to the dowels. Ordinary nails for these purposes will not work.
Fasteners liquid nails is convenient because it is very easy to install, it also possesses the great strength of the adhesive composition. Liquid nails applied to the back side of the mirror in small portions at equal intervals. On the edge of the adhesive applied is that it does not leak out. After fixing the mirror must be locked for a time sufficient for setting of liquid nails. If the weight is large enough, would require a special backup for 24 hours.
A mirror to the surface of the plasterboard can be attached using double-sided tape, not any, and that, in the instructions that says that it can be used for mirrors. In this case the tape is pasted on the entire inner surface of the object and is pressed against the wall for a few minutes. Some manufacturers produce water-resistant adhesive tape, which can be used for bathrooms.
To attach the mirror to the drywall with dowels, it is best to use special anchors-butterflies, they have a locking collar, not allowing the mount to fall into the hole and eliminates the possibility of turning. And by this , the dowel is attached a hook, bolt or other suitable fastener. For the heavy mirrors on the wall additionally modify another sheet of drywall or plywood. An alternative to dowel butterfly can become the anchor bolts.
In addition, at present some firms are ready to provide a special system for hanging mirrors on drywall. It consists of brackets, profiles, and fasteners specifically for this wall material. The system is attached to the surface, and into it is inserted the mirror.