Once when I was a wee-er Cherry, I was
really into buttons. Got every single one I could get my hands on. One day I decided it'd be hella to wear a completely plain T-shirt in a nice color and just cover the chest in buttons. I got compliments! And also when I took them off at the end of the day, my shirt was riddled with tiny holes. That shirt had tiny pinprick holes on it for the rest of its life.
The moral of that story is
don't put pins on your shirts. At least not T-shirts.
Personally, I put them on my backpack. Lots of backpacks have some little flap over them or similarly small, sectioned-off, prominent space that's great for filling with pins.
One or two, well-picked and well-placed, can look quite nice on a purse. Best layout is two buttons, one bigger than the other, pinned close but diagonally from each other.
Same arrangement can look very nice on certain hats. Slightly off to the side - above your temple or close enough.
If you're of the inclination to layer things over collared shirts, I've seen some people pull off wearing a pin on said collar. But beware. As I warned... holes. But if you find yourself with a stained collar, this might be the way to hide that and bring some life back to the shirt. My queen ALB did this look in
this A+ video if you need a visualization of the look.
Beyond things you
wear, you could also get a bit creative and use them as decoration. Putting a nicely patterned fabric in an embroidery hoop, putting a couple choice pins on it, and hanging it on the wall could look really nice. Likewise, a throw pillow could be jazzed up by some neato pins on an upper corner (but beware - some pins don't like to stay closed and are liable to pop off - don't want to snuggle up with a cuddle ball of ow what the fuck poked me). I used to have a full length mirror that had this unusual frame - it was like one of those bulletin boards with the batting, fabric, and ribbons across it (
you know), and I stuck all my pins to that once they ruined my shirt.
tl;dr: put them on literally anything made of fabric.
