There are many methods of meditation that can lead to channeling, mediumship, or simply a greater spiritual awareness.
Here is the method I use:

1. Find a comfortable position, either sitting or lying down.
   Close your eyes.
   
2. Take three or four deep breaths, inhaling through the nose and exhaling through the mouth.
   
3. Concentrate on your body and mentally tell each part of your body to relax, from the toes on your feet to the muscles in your face.
   
4. Tense some of your muscles, then let them relax.
   
5. While in this relaxed state, visualize the colorred.
   Breathe in the coulor red and exhale the color red.
   
6. Move to the color orange.
   Breathe in orange and exhale orange.
   While you are visualizing this color, allow your emotions to relax.
   
7. Move to the color yellow.
   Breathe in yellow and exhale yellow.
   Allow your mental activity to cease.
   Hold only the color yellow in your mind.
   
8. Move to the color green.
   Breathe in green...
   exhale green.
   Allow peace and healing to surround you, and penetrate you.
   
9. Move to the color blue.
   Breathe in blue...
   exhale blue.
   Feel the Love of God encompass you.
   
10. Move to the color indigo.
    Breathe in indigo...
    exhale indigo.
    Concentrate on your dreams and aspirations.
    Feel yourself going deeper and deeper within.
    
11. Finally, concentrate on the color violet.
    Breathe in violet...
    exhale violet.
    Tell yourself you are now in touch with your spiritual self.
    
12. From here you can journey to a place in nature, such as a beach or a mountain, where you can be alone and can feel at peace.
    

Sometimes when you have reached a deep state of meditation, you will begin to see swirls of color, see mental pictures, or internally hear a voice talking to you.
Take note, and keep a journal of any impressions.
Come back to normal consciousness by visualzing the colors in reverse sequence.