Use wooden trim, PVC molding, or reclaimed wood—cut to size, sand, paint/stain, and attach to the mirror edges with mirror adhesive or clips.

Use waterproof LED strip lights with adhesive backing, installing them on the mirror's back edge or a recessed frame. Connect to a GFCI-protected circuit with a dimmer switch for adjustable lighting.

Yes by applying one-way mirror film to clear glass, but proper lighting contrast (bright on one side/dark on the other) is crucial for the effect to work effectively.