Seeing people's energy - and learning to interpret what you sense.
Go to a mall, a park, some public place, and allow yourself to watch people without attachment to particular outcomes. As you're watching them let your vision float, attached to nothing. Then, just allow the feeling of how they are made up to come to you.
At first, you will get large nebulous impressions, such as angry, or sad, or depressed. As you practice, the feelings will become more specific and you will see things like alcoholic, abusive husband, specific health problems, personal history, etc. Just remember to remain detached, as though you're a thousand miles away, and what is moving them is of no importance to you - you are only a witness. It takes practice but this is a good place to start.
