I have a neat trick. I say "if I were a me, where would I have put this?"

I don't remember where things belong, but I know immediately that I would put vitamins in the cabinet, on the counter, on the table, or in a travel bag. There's basically nowhere else I'd put them unless something very unusual happened, so then I'd look to see if they fell from one of these places

In such trying moments I like to direct my friends to the next logical line of inquiry.

Sometimes in the span of ten seconds.

Clean the house. Put important things on THIS bookshelf. Wait, maybe it was this one. Wait, maybe it was....

Look for something else instead, you'll have to move the original thing to try find the new thing.

I setup a camera in my workshop just because of this... now instead of spending time looking everywhere I'm looking on the footage to see where did I have the thing last time

Irony: I clicked this post twice in two minutes even though the thumbnail is clearly recognizable

What usually works (when I remember to do it) is imagining a grenade going off wherever I put the thing down.

Page markers and a label gun will become your best friend. That and a personal journal you struggle to write in because you never memorized spelling. Yes, I'm looking at you.