Whether you’re hanging a picture or a heavy mirror, you need good wall fasteners to hang it on. In the business it’s called a wall anchor and, when possible, it should go into a stud or other solid framing material. But often this isn’t possible, depending on where you want it hung. Then you wind up putting your anchor into wallboard and crossing your fingers.
You need wall fasteners designed for wallboard. There’s plenty to choose from: molly screws and toggle bolts and anchors that drive in, screw in or expand in the wall. The real secret is using one that’s designed for the weight you are hanging. If it’s big or heavy, use larger fasteners and more than one, to share the load. Always drill a proper size pilot hole first. Don’t overtighten your fastener as it could damage the surrounding wallboard and weaken the anchor’s holding power