(1) A man is but the product of his thoughts. What he thinks, he becomes.
If you think sad thoughts, you will feel sadder, if you think happy thoughts you will feel better. If you think you can do something, you empower yourself to be able to do it. What you think becomes real for you.
(2) Happiness is when what you think, what you say, and what you do are in harmony.
If you think you should do your homework, tell your teacher you will do it and then actually do it and turn it in, you will feel good about yourself. When your thoughts, words and actions match, you are on the right track.
(3)Live as if you were to die tomorrow. Learn as if you were to live forever.