What's that? You found a mirror in a bin?
Job 1: assess the crap foam on the back of the mirror.
Yep pretty crappy. Gotta get rid of that.
Job 2: carefully scrap off the crappy foam. I recommend a BUTTER KNIFE as they are blunt. You could also use a paint scraper, a hard piece of plastic (like a bank card or your Medicare) or even peel it off. Keep in mind the more foam you get off the mirror now, the stronger the bond foe the new tape will be.
I'm sure at this point most people would tell you to clean the mirror and/ or the wall. I didn't. Firstly because I don't like reaching as it hurts but mostly because I forgot.
Job 3: admire your mirror. Clean it, don't clean it. Your choice. I went option 2, obviously.
It's at this point you want to decide where to put your mirror. I chose a wall in our bedroom that wouldn't reflect light back into us. Other suitable places to mount a mirror are: the back of your bedroom door (an under-utilised space), in the bathroom, toilet or laundry (remember to account for wet areas, steam and humidity) or even inside a closet (if you have only hangers, you can hang a mirror that you can use by "parting" the sea of clothing.
Job 4: attach lots of short pieces of double sided tape. You can choose to use long strips but I think you will find it doesn't look right. You can choose to use 4 pieces (like the markings from the crap foam) however I chose to use an entire roll of Permastik 1m x 24mm White Heavy Duty Indoor Mirror Mounting Tape Roll [found at bunnings here:
https://www.bunnings.com.au/permastik-1m-x-24mm-white-heavy-duty-indoor-mirror-mounting-tape-roll_p3...] that MIL got for us in April 2017. I figured more was better when it comes to sticking stuff up!
Job 5: make your husband stand there holding the mirror to the wall. It'll take a minute or so. The hold takes a few hour, curing over night.
Brush your hair, change your clothes and take a selfie!