You may think this is odd, but this has always worked for me. First, "pray" to St. Anthony! I am not Catholic by any stretch of the imagination, but saying the prayer "St. Anthony, St. Anthony, please look around, something has been lost that must be found!" usually works. Just think of St. Anthony as a friendly spirit in another dimension that can help you. Just like how you ask a human librarian to help you find a book, you can ask a spirit who is considered a saint in a religion to help you find lost things you can't find.
Also, imagine that feeling when you just found the item that is lost -- that feeling of excitement exploding in your chest [no, not a heart attack]. Just imagine that all the time, that "I FOUND IT!" feeling -- you can also practice your IM by doing this. It's easy and always works!