Practice concentric visualizations, from the nearest to the neediest. Here is an exercise you can do anytime.
Close your eyes and visualize yourself giving a generous smile to the person in your life you love most. Now open your eyes. How do you feel? Imagine that person smiling back and laughing with you.
Next, close your eyes and visualize yourself giving a generous smile to someone who is just an acquaintance, and feel that same response and laughter.
Finally, close your eyes and visualize yourself giving a generous smile to someone who you think is really in need of help, and feel that response and laughter. Then, imagine how you can help that person, and go out and do it.
— Stephen G. Post in The Hidden Gifts of Helping