You need a paper and a pencil, then you close your eyes, slow down your thoughts and then start to draw. You just follow the pencil without thinking what will come out, or thinking about what do you draw.
It is a good feeling to 'just' draw without any thoughts and without wishing to draw something 'concrete'. You just relax and follow your inner self. Or you can choose one word to 'meditate' on it and draw while you're thinking of it...
The picture might turn out as interesting as this one:
Try it and tell me how do you like it! I always have lots of fun when I do that - I hope you will enjoy it too!