There are an amazing number of resources available on Affirmations (Stay tuned for Website Wednesday!) so you have a lot of options, from daily email subscriptions to software that will run little messages across your screen, to strategically placed sticky notes, hypnosis, subliminal messages in your sleep, to simply waking up each morning with a positive attitude.
As to how to use them effectively, here are some quick tips from a more comprehensive paper on the topic: Daily Positive Affirmations: Achieve Anything Your Heart Desires With Positive Affirmation.
* Use positivity. Avoid negative words like "can't", "don't", "won't." So, instead of saying, "I won't eat like a pig," you could say "I will eat like a sweet little bird." (Beware that birds eat a lot.)
* Use present tense. So I guess I was wrong on the last one. Instead of "I will eat like a sweet little bird." say "I eat like a sweet little bird." (Oh... one other note related to birds and current events, I read today about 3000 birds falling out of the sky in Arkansas, so perhaps birds are the wrong animal altogether..)
* Use brevity. Let's forget about the birds: "I eat healthy foods."
* Positive affirmations must be uttered and thought repeatedly: "I eat healthy foods. I eat healthy foods. I eat healthy foods. I eat healthy foods. I eat healthy foods." (you get the idea.)
* Repetition leads to auto-suggestion which is like brainwashing. However, before getting all concerned about "drinking the kool-aid" the difference is that you are the one in control of your thoughts, not some psychopath. (I guess this is sort of like brainwashing yourself, but only into doing something you really want to do...)
* Be passionate about the goal in mind. If you really don't care about eating healthy foods, repeating "I eat healthy foods" a bunch of times is probably only going to annoy your mind.
* Believe in your affirmation. If you don't really think you can eat healthy foods, you probably won't.
There you have it! For some reason, I'm hungry for a healthy breakfast!