'Always Maintain a Joyful Mind: and Other Lojong Teachings on Awakening Compassion' by Pema Chodron is very easy to use every day to give you something useful to focus on. I could say something 'spiritual' to focus on, but that could put people off who don't believe in God - these teachings are useful in taking us outside of our inward-looking selves, our egos, whatever we believe.
It consists of 59 'slogans' or one-line instructions designed to wake you up. They are ancient Tibetan 'lojong' teachings. Each slogan occupies a page, and on the opposite page there is a short commentary by Pema Chodron. The idea is that you open a page every day and let that be the theme for the day.
Pema Chodron is a Buddhist nun and teaching director in an abbey in Nova Scotia, who has written many popular books on Buddhist teachings. She is American; I think she is popular as she can make Buddhist teachings understandable to a Western audience without diluting their power. For example, the slogan "Don't talk about injured limbs" has her commentary: "Don't make yourself look good by disguising others' weaknesses." About "Don't be so predictable" she says: "Don't hold grudges against other people."
What I particularly liked about this book is that Pema Chodron emphasises how we ourselves benefit from behaviour that may look purely altruistic: being generous, kind and less reactive decreases our own suffering as well as that of other people. I guess that's the point of Buddhism: we look at the blissful face of Buddha and think he got that way by meditating, but that's a Western misconception; he got that way by practicing letting go of his selfishness and developing compassion - and became blissful as a result!