Affirmation is a chanting of positive sentence with strong beliefs that it is true. The basic difference between autosuggestion and affirmation is that while one could be either positive or negative, but the other one is only positive. Hence, affirmation is regarded as a great tool to get through rough patches and excel in life.
To make affirmation work for you, you need to make your desire in sync with your emotions and behaviors. Your desire is a product of your conscious mind, and you chant positive affirmation through it but your emotion and behaviour is a product of your subconscious mind. So while chanting to make sure your attention is totally dedicated to your desired positive affirmation so that your subconscious mind absorbs it and makes emotions in sync with your desire.
Practicing whatever you desire is also vital to make your affirmation work for you. It removes the doubts from your mind, which is a stumbling block to realize your desired goal. If you have doubts in your mind, the impact of positive affirmation reduces. Hence before making positive affirmation, try to take help of meditation first so that your conscious mind becomes still and does not interfere while chanting affirmation and create doubts.
Finally, always keeps in mind that whatever positive affirmation you make your subconscious mind absorb the affirmation and distribute it to the rest of the body and surrounded energy field to attract the situations and circumstances in accordance with your desire to realize it sooner. You can make an affirmation for good health, healthy relationship, success in life, etc. to make you life much more fulfilling.