The stability of your leaning mirror has to do with how thick and stable the base is, the mirror’s height and size, and how much friction there is between the mirror and your flooring. If you’re placing a wood-framed mirror on a hardwood floor, add some rubber grips or furniture strips to the base to keep it from slipping and sliding. You can take it a step further by adding furniture straps to the back of the mirror, or by anchoring the mirror to wall studs or using drywall anchors to secure the mirror to the wall.