The #1 rule for this sytem is that things should have exactly one home. Examples:

• ear warmers: coat left inside pocket
• mittens: coat pockets
• hat, neck warmer: coat liner pockets
• laptop: backpack
• phone, handkerchief: left front pocket
• keys, wallet: right front pocket
• work badge: right back pocket

As much as possible, if I take something out I immediately put it back where I got it. My keys should only ever be either actively in use, or in the specific pocket they go in. When I change pants, I move everything over from my previous pants.

Some things need to stay out of their homes for longer periods: my laptop goes on my desk at work and on the charging shelf at home. There's still a primary place for it, though, a pocket in my backpack. Any time I put on my backpack, my laptop has to be in there. And any time I leave a place that isn't home, I wear my backpack.

One thing that makes this work is that my backpack feels different with my laptop out of it: lighter and less rigid. So if I put my backpack on without my laptop I feel right away that I need to go get my laptop. Similarly, my phone lives in my left front pocket. If I start to walk somewhere, and my phone isn't in that pocket, I'll notice right away and go back for it.

This works well because I only have one backpack and coat, and I always wear the same kind of pants, so anything that feels different is very apparent. I can't feel everything, like my keys, but this has saved me many times with my phone. The only time I lost my phone was when I had just gotten a new phone but hadn't moved everything over yet. I was keeping both phones in my left pocket, and so when I walked off only one phone in my pocket my "there's no phone in my pocket" alarm didn't fire.

(Another thing this relies on is pants having useful sized pockets. If you have pants with minimal pockets I recommend sewing bigger pockets. Two years ago my family got really into this at Christmas and my female cousins all extended their pockets to fit their phones.)