Everything accomplished by humans began with a thought. Thoughts are road maps for the spirit. It's been said that whether you think you can do something, or think you can't — you're right. The use of affirmations is a simple way to provoke specific positive thoughts for yourself. They're a way to choose your own station on the radio — instead of just listening to the pre-sets.

Affirmations can make positive things happen
More and more people are becoming aware that thoughts really do help make things happen on the physical plane. For example, in the body an embarrassed thought provokes a blush. A simple example, perhaps, but a good way to illustrate the point that intangible ideas can have distinct physical effects. 

By using affirmations, it is possible to re-program some negative thoughts towards effects you'd like to see in your emotions or in your body. You'd be amazed at the changes people can make using affirmations. 

Affirmations are purposefully crafted in positive language — “I easily accomplish...” rather than “I no longer struggle with...” — and as though the desired outcome is already present on the physical plane in the here and now: “I gratefully receive...” rather than “I will get...”

Affirmations can help you overcome fears 
If you find you have a lot of resistance to an affirmation, such as “Oh, golly, there's no way that one's gonna come true,” sometimes it's helpful to spend time writing out your responses.  Doing this might help you learn more about the voices that speak up when you see something you deeply desire. These voices and their objections give you a place to start to create your own custom affirmation program. Once you identify your fear — your particular inner block  — you can turn it upside down and state it positively for yourself.

For example, let's say you have a block about public speaking. You think about doing it and a voice comes up that says, “Who are YOU to be pretending to know more than these other people?” Upside down, that might become an affirmation like, “I am confident of my expertise” or “Other people are grateful to hear my wisdom.” 

Often, the best affirmations are the ones you write for yourself, in your own language, directed towards your specific issues. 

More information
There is a large and growing body of literature about the power of visualization and affirmation. Closely allied to techniques of self-hypnosis and autogenics, this approach is being increasingly used in conventional medical settings. If you'd like to learn more, popular authors are Shakti Gawain (Creative Visualization), Louise Hay (You Can Heal Your Life), Wayne Dyer (You'll See it When You Believe It), Bernie Siegel (Love, Medicine, and Miracles), and Jeanne Achterberg (Imagery in Healing).