I read about the power of affirmations years ago, in a book by Catherine Ponder, a Unity Church minister. She suggested adding these words to every affirmation: “In an easy and relaxed manner, in a healthy and positive way, in its own perfect time, for the highest good of all.” - Marc Allen Interview
The interview is peppered with good quotes. It is one of the best sources of motivation that I came across.
P.S. I also tried the "power of affirmations" and trust me - it works!! =)!