How can I know the difference between right and wrong thinking and acting?
Everything begins with thought. Each person has freedom to think as he pleases. Thinking controls all action, and all physical activity. Responsibility for thinking is something that each individual must assume, sooner or later.
If what you are thinking comes into form or action in a way to benefit everybody, it must be right or correct (based on divine principle).
If what you think would injure, interfere, or hurt anyone else when it comes into form or action, it must be erroneous or incorrect.
Therefore, study Truth and learn to think constructively (for the good of all, yourself included).
The only thing that is always right is the right, perfect action of Divine Mind, which is always taking place through spiritual man. Therefore, link up your human phase of mind with the divine by saying often:
I let the mind of God direct my thinking, and I find myself doing the right thing at the right time in the right way, governed by God. I am at peace always.