As you'll see, it can look great:

https://www.houzz.com/photos/mirrored-wall-phbr0lbl-bl~l_37947

They do look great but they are all new, can I drill into my existing mirrors to add a design or change the look?

You can glue lightweight material on the glass but you can't drill through it.

You should be able to attach moulding to mirror with clear silicone and tape it until the silicone dries. I know you CAN drill through mirror with the proper drill bit, but then you'd run the risk of cracking. Just make sure that you paint ALL sides (including the back) of the trim pieces. Another example

I have used mouldings that were attached to my mirrors with silicone, so I can tell you that it will work just fine. Take advantage of your mirror it can look amazing. I know that the large mirrors in my home make a huge difference in many ways. Mirrors help to make rooms feel larger, they help to bounce light around the room, especially if they are opposite or near another window. I love the architectural interest I have created with the use of mirrors and moulding in my home ( shown below ). Best of luck !

They look to be in great shape and I think they are actually very much in style!

I would work on other aspects of the room to bring it up to date and embrace the mirrors. First thing I would do is to remove the art hanging over the mirror.

Show us more pics and we could add other suggestions.

No pics in your idea book, so not sure of your style?

I love Mark's idea. The wall in the first shot looks like a wall of French doors - how beautiful!

the black frames above would look great in your room

Wow leave that beauty !

I agree totally with Mark's idea. You can really do it up with the mirror and make it look exactly like you want by using silicone. All you have to do is buy something that you love, like the french door look, or draw a design you love and have it made. As long as they have the exact dimensions, it can be done precisely. But the dimensions have to the done exact.. You could even frame them with wood painted to your liking so that they look like individual mirrors and hang artwork in front of the mirror to give the wall interest. Please don't even think about drilling through the mirror, unless you have a professional do it. It does look good like it is, but the art you have in front right now just doesn't fit in. Make the mirrors conducive to art. One other thought - you could have these mirrors trimmed in beveled glass mirror strips around the edges. That's what I did in another house I had and it added so much more interest - more bling! Best of luck!

I have this Large Mirror in my Apt from the 70s. Makes my place look bigger but would love to do something to it. Any Ideas???

Wendy Salle….show us your final results.