Depending on your level of anxiety over losing your item, you might want to do something like p3nathan's lovely Spell to Calm Anxiety first so you're calm enough to focus on doing this spell properly, since pendulum work takes a bit of concentration. It will all work itself out, one way or another. Everything always does.

Anxiety is taking its toll,
So I speak these words with my heart and soul,
To calm the storm that rages inside,
Take my worries and cast them aside
[see full spell details here: http://everythingunderthemoon.net/forum ... t24168.htm]
To find lost keys, for example:
1. Draw a floor plan of your home.
2. Make a pendulum by tying a small key to a string.
3. Hold the string in your left hand, and run the fingers of your right hand down the string, starting at the top and ending at the key. Do this three times while saying: “Tell me yes.” Watch the movement of the key. Do the same thing again, three times, while saying: “Tell me no.”
4. Hold the pendulum over the floor plan and ask: “Are the keys in my house?” If the answer is yes, start moving the pendulum over the floor plan, stopping in each room, and asking: “Are the keys in this room?” Once you get a firm “yes” answer from the pendulum, go to that room and search for your keys. [er, if the answer is "no," come up with a contingency plan of some sort, hehe --Kassandra]
5. Remember to thank the pendulum for its help.
Source: llewellyn.com/spell.php?spell_id=1919
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Here's another approach, somewhat similar (it's good to compare):
http://www.youtube.com/watch?v=O3adWIrSPYE
She makes a great point about practicing this exercise first when you haven't really lost anything just to
sharpen your psychic senses. Have someone you trust hide something from you. Hone which methods
work for you. Make notes in your BOS. Then, you'll be ready when you've really lost something!
I found some insightful comments on YouTube beneath the video above, posted by one, "Terry Slaughter," that really resonated with me. I included them below, followed by my comments. Hope you find this helpful.
Terry wrote: "I can find lost items psychically by sensing them, successful 9 of 9 recent attempts. When I listen to this video, I note that you are using the pendulum in your right hand, which is controlled by your left-brain, which is the subconscious and can tap into the universal knowledge beyond time. I suggest one never "search for the items" but instead, keep testing from different locations, triangulating until it points at one certain spot. Then look... and be amazed. It works."
Note: Ha, she said the magic word: triangulating! It's long been my opinion that what we call divination is essentially "triangulating." This is reflected in, for instance, when a psychic reader asks you for information like your birth sign and date, or which city/country you live in, or asks you to repeat a word such as your first name 3 times. With these methods, they are triangulating your unique energy signature (I believe that every one and every thing has a unique energy signature, which Terry in her quote calls a "signal").
I also believe that while probable outcomes could be triangulated in 3D space/time, still, one's actions could change which probable outcome actually becomes the end result. Therefore, it's never a good idea to place all your eggs in one basket, so to speak, when you get a psychic reading, or have other divination done for you. Better to view such services as only ONE triangulation of ONE possible outcome AT THE MOMENT of that reading. --Kassandra
Terry wrote: "One thing I've learned from my experiences is that each item you search for has its own signal. One of the first items I successfully located was a friend's keys. In fact my first five locates were keys. But then one day, she came and asked if I could locate her cell phone... so I gave it a try... and sensed a direction... went there... and found her keys again! A few moments later, I did locate her cell phone, but only after recognizing it had a different weaker feeling or signal."
"We're really just learning how to make our conscious mind shut-up and observe what the sub-conscious mind is suggesting. This isn't about 'thinking.' Understand that your sub-consciousness gives constant signals that you're usually too busy to detect. And like gravity, the truth is just there, and 'belief" is NOT required. It doesn't suddenly come to you. You come to it. It's been there all along. This is mostly about learning to calm the chattering monkey in your mind. Ask. Trust. Follow."
Note: I've also been of the opinion that if we think psychic abilities and magical workings are about "thinking" and otherwise left-braining things to death, we might as well forget them both. These are intuitive processes, meaning to me that while "thinking" is of course involved ("energy follows thought" and all that...), with psychic stuff at least thinking should work in service of intuitive ability, not in lieu of it.
I think Einstein described it best when he said: “The intuitive mind is a sacred gift, and the rational mind is a faithful servant. We have created a society that honors the servant and has forgotten the gift."

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