Routines help reduce stress and if you make a place for the things you know you'll need a place for, you'll also reduce clutter.
I have a laptop backback that I use every work day and a wallet I use the rest of the time. The pack has a pocket where I put my phone and my wallet. It also has a springy plastic coil clipped inside it to which I clip my keys. It's long enough that I can lock or unlock the front door without having to unclip them. My keys are always left in the right spot instead of in the door, a jacket pocket, on the stairs, etc.
The bag has a big pocket where I put the things that need to be taken from home to work or vice versa. When I arrive and take my mobile phone out to plug it into the charger (and, yes, I've got one of those at each end, so the phone has its place too), I also check that pocket.
As for pocket accumulations, I have an attractive ceramic pot on my dresser into which I drop all my non-quarters change. The quarters go in an old family heirloom, a little silver baby cup, where they wait until laundry day.
And the mail gets sorted in the kitchen where all the junk & empty envelopes can go right into the recycling. I have a pretty tin inbox for the remaining incoming paper (and that box also has a pen, the stamps & return address stickers for outgoing mail).
When I need to remember to take something with me when I leave the house (e.g. drop this Netflix DVD in the mail on the way to the metro), I just set it at the top of the stairs where I can't miss it.
When I shared a household, we always put the rotating chore wheel (made out of cheerful construction paper to lessen the pain of cleaning duties) on the fridge to indicate who was doing what this week. As a kid, that's also where I could see the menu plan of who was cooking what each night. And, of course, that's a great place for the shopping list.
Figure out what you need and where you need, then set things up to make it all flow smoothly.