Do it, and then you will feel motivated to do it.
The first step in solving a problem is to recognize that it does exist.
Attitudosis cannot survive a strong, steady dose of uplifting literature or a regular donation of your time to a good cause. Make eye contact with someone who doesn't expect it and then give her your best smile. When you are willing to improve your attitude and you take action to do so, you'll enjoy life even more.