The first bit of advice reminded me a lot of something I read in
"The Art of Spiritual Dreaming" by Harold Klemp, where he describes interpreting "real-life" situations as if they were like dream symbols to be interpreted. I don't usually go for subjectivism, but I love dreams, so I thought that was a realy interesting perspective.
The technique I use, that a friend of mine taught me:
1. Visualize the lost item, as clearly as you can.
2. Visualize a string made of golden light, one end tied around the object.
3. Feel or visualize a length of that same string in your hand.
4. Open your eyes and start "pulling" on the string. I make physical motions in the air of reeling it in, which looks silly but it works.
5. Follow your gut feeling as you follow and reel in this "string".
It sometimes leads me all over the places that I left the item, but works out in the end most of the time.