oh, you're definitely not alone there. i mean, sheesh, sometimes i can't find a thing that i "put somewhere" half a minute ago! i think (at least in me) it could be connected with the fact that i'm too concentrated on organising and memorising non-material things, ideas, plans, relationships, so the material world can kind of.. get a bit distant. one way in which i try to cope with this (it's quite funny, so please don't laugh) is when i see that i have lost something again, i try to think of the thing as a, well, person, related to me in some kind of a more personal way than just "belonging", and try to remember/imagine where it could be in this manner. it's almost like, well, not really talking to the thing (though sometimes i do that, too, have to admit, eh), but trying to get in touch with it not through rational memory but some, umm, special connection you have with it..? i don't know if this is easy to understand, but that's what i do most of the time in such situations.
or just try to put things in some weird places where i am sure to run into them sooner or later, like on the doorknobs or on top of the computer where i wouldn't normally put anything, so that i'd notice them without even trying
hope this gives you some ideas how to deal with the forgetfulness.
though i suggest you just don't worry about it too much, because for me it got better when i stopped worrying about having lost something again, the calm helped to focus on finding them, somehow.
