People have to be responsible for their thoughts, so they have to learn to control them. It may not be easy, but it can be done. First of all, if we don’t want to think certain things we don’t say them. We don’t have to eat everything we see, and we don’t have to say everything we think. So we begin by watching our words and speaking with good purpose only. There are times when we must have clear and pure minds with no unwanted thoughts and we have to train and 
prepare steadily for those times until we are ready. We don’t have to say or think what we don’t wish to. We have a choice in those things, and we have to realize that and practice using that choice. There is no use condemning yourself for the thoughts and ideas and dreams that come into your mind; so there’s no use arguing with yourself or fighting your thoughts. Just realize that you can think what you choose. You don’t have to pay any attention to those unwanted thoughts. If they keep coming into your head, just leave them alone and say, “I don’t choose to have such thoughts,” and they will soon go away. If you keep a steady determination and stick with that purpose you will know how to use that choice and control your consciousness so unwanted thoughts don’t come to you anymore.
An excerpt from Rolling Thunder by Doug Boyd
Appearing in Bobbi DePorter’s The 8 Keys of Excellence: Principles to Live By