If you have any experience with affirmations, you probably have found that they don't always work, or worse, produce the opposite of the intended effect! That has been my experience with affirmations. It's not that affirmations don't work -- they do. The problem is not with affirmations, but with ourselves.
To give an example, have you ever noticed yourself promise to someone you will do something, but then not do it?
Or we make a New Year's resolution, "I'm going to lose 10 pounds this year". Once the year is through, we might have even actually gained weight. Guess what? Yet another instance where what we said would happen doesn't come true.
Over time, instances like these accumulate in our unconscious mind -- where what we say is going to happen, doesn't actually happen. The result is that our unconscious mind eventually stops believing in what we say.
How can affirmations work if this is the case? They certainly can, if we retrain ourselves to once again believe in what we tell ourselves. There is a very simple way to do it detailed in this awesome report.