I saw a tutorial on this site , awhile ago , someone made a frame for the mirror , it actually layed on top of the mirror. She hung the mirror , then attached the frame to the mirror by using command hook hanging strips.
Hi! Here are some great ways to make a frame for a mirror. There are some cool ideas! https://www.hometalk.com/search/posts?filter=diy%20mirror%20frame
hometalk has some ideas!
Here's how I framed a bathroom mirror.