Designate a place in every room as, “the place I put things.” Use positive reinforcement to train yourself to put things down in that space. Every time you use a drop zone, give yourself an attaboy/girl. It needs to be big enough that it can hold a few things, keys wallet, cell phone, but not so large that things can get lost in it. You don’t want too many drop zones, but you need to have one always handy. Keep them uncluttered when possible so that they’re always available. Dissuade the people in your life from “cleaning up” these spaces. Now, when you lose something, you’ve got a good chance of finding it by checking all your drop zones.
I live in one of those tall but small/narrow places with multiple sets of stairs - one thing I noticed within myself was a resistance to going up/down one or two flights of stairs just to put a thing in its right place. I put ‘drop zones’ at the base and top of stairs and I just grab whatever’s there on my next trip up or down. In between I completely forget about those things, but I see them again and pick 'em up when I’m headed up/down and then - well, I’ve got it in my hand so I might as well put it where it goes.
This works to put things in the right spot, but then I often forget the real reason I went up/down those stairs in the first place XD