I'm so bad at losing things in plain view, that I developed methods to try and avoid the problem.
1. I have a block of wood drilled to hold my knives. It also stops them from rolling off the table. This, of course, only works when I actually use it, which appears to be about 25% of the time.
2. I use the bottoms of model boxes to hold parts I'm not working on, the tops to hold parts I have painted or glued, and a lid off a shoe box for the parts I am working on. I've yet to lose any small parts, and I'm not too worried about the large ones. Yet. Since I was using the kitchen table for building, I got into the habit of using ziploc bags to put the parts into for storage until next time.
3. I tend to paint small parts on the sprue. Yes, I have to touch up the paint later, but I figure it's better to paint the part twice, then paint it once and never see it again!