http://home.intekom.com/innerhealing/af ... mirror.htm
I really like how they talk about losing eye contact and fidgeting - you can see what your ego doesn't believe, and wants to keep the same. This happens to me all the time and shows me exactly what area I need to explore or change.
I know not everyone is down with mirror affirmations (or affirmations for that matter), and that's cool. But for those that are interested and believe they work, and also help build awareness, the above link has some great information. I find that I feel very empowered during and after them, and throughout my day when negative thoughts arise, it's much easier to let them go and the new "programming" steps in and says, "that's not true, you are amazing" or whatever the case may be. Eventually these thoughts will completely replace the negative ones, and become normal.
I do think mirror are the best form, and better than written affirmations, because you are face to face with your self visually and really get to see how you feel about yourself as you go through the affirmations.