Simply, thinking positively, imagining situations where all is well and that you are healthy, you will create irreparable without other efforts, what you think. We know that the images that we think are of information and that it is translated as energy and matter.
The effectiveness of this approach is well established. For example, patients with cancer and after heavy treatments can imagine, visualize chemotherapeutics rather as a golden liquid that penetrates inside the cancer cells to their death, rather than a toxic and destructive product that comes damage your body and you cause suffering. Thus, it was observed that patients experienced less side effects of treatment (nausea) and white blood cells multiplied.
Visualization is therefore an excellent therapy, affecting our body (increase the immune system) and improves our lives (successful coincidences), which aims to transform deemed uncomfortable situations in comfortable situations.
A battery of exercises (concentration, relaxation, etc.) are available to view as possible. However, I found some of these exercises relatively difficult and incomplete.
This book remains a reference about the strength of our thoughts!