Before you set something down and walk away, ask yourself this simple question: "Is this where it goes?"
If the answer is no, then take an extra minute to put it where it does go. This may sound like a pain in the rear, but it's a habit that pays off big. Ever lose those keys or that letter you're working on or your fancy pen or the roll of tape? Then you can imagine what I mean. This is particularly helpful if you aren't the only one living in your humble abode and, if that's the case, you'll want to enlist the participation of everyone else in this simple but effective strategy.
This assumes, of course, that you actually have a place for things. If you don't, then we have a lot of work to do, don't we? And we'll get to that. We will. My bet, though, is that you do have a place for those commonly-used items and if they wander away and don't manage to find their way back, you know the frustration that can cause.
This strategy also helps as we become older and our memories become less, shall we say, effective. If you have young people around, enlisting their support will help them build good habits and develop good organizational skills that will last a lifetime.
Have a two-story or more-story house and have something that needs to go upstairs or downstairs? We'll look later at a special strategy for dealing with that designed for those of us who aren't into getting our cardio workout in using the stairs at home.