The exercise with the pendulum is simple. Every evening spend some time–starting at ~5-10 minutes every evening and gradually increasing over time at a comfortable pace; never do it until you get tired–hold it in your writing hand and, gazing into the pendulum, will it to move nothing but sheer concentration. Be sure your hand is steady and that you are not simply subconsciously moving your hand slightly. The meditation in dead stillness will help with this. To further help with this you will want to work the pendulum up to a nice, broad swing, then make it stop, then change directions. For instance, start by making it move back and forth until it has a wide swing, then stop, then make it move from side to side. Or go clockwise, then pause, then counterclockwise. Experiment with this. Once you set your mind on making it move in a particular direction and in a particular manner, do not change your mind. Set your mind on one thing and do it.
Do this exercise with the dictum in mind that the observer is not separate from that which is observed. If necessary, gaze into the pendulum and imagine that you are inside of it, to the point where you actually **feel** as if this is so.
To help induce the trance state needed to make this work, you may choose to do this in the dark by candlelight, perhaps hypnotizing yourself with the candlelight before starting. You can also further develop the skills needed to do this successfully by working on developing the blood centers located in the hands–see the exercise for creating energy balls.
In order to attune the pendulum to your own energy for maximum effect, consecrate it using your own blood at some auspicious time.