Recommending this book by Don Miguel Ruiz, a Toltec spiritualist teacher. Although much of the teachings originate from the Toltec tradition, the concepts are not religious at all, and can be applied to anyone of any (or lack of) religion. Just applying these four simple principles in your life will change how you treat yourself and others. As with new habits, take your time, but be firm with the intention and determination to improve the quality of your life (ie. practice!!).
Here are the four agreements, for your reference.
Here's a link to the audiobook, if you would like to listen to it on your walks/drive to work! Nevertheless, I would recommend both reading and listening to the book. Sometimes you can get different insights when being exposed to the material through different senses.
As usual, you know where to find me if you would like to discuss the material~