I don't know if there's more to it than these two sides of the same coin, but every time I move house, when I pull something out of the box and go to put it "away," wherever it's going to stay from then on, I close my eyes for a second and think, "If all I knew was that I had already unpacked this, but I couldn't remember where I'd put it, where would I go look for it first?" and then I go put it there and that becomes its home.

Check out Dana K. White. She uses this principle along with 5 other "rules" to declutter. Has really helped me get my space in order.