Moved by the poverty he'd seen on his travels, Jim Ziolkowski gave up a lucrative career in finance to start buildOn—a nonprofit that runs after-school programs in disadvantaged areas of the U.S. and builds free schools for children around the globe. His new memoir, Walk in Their Shoes: Can One Person Change the World? details his experiences in the south Bronx, Mali, Haiti, Nepal and Detroit, as well as chronicles the lives of the kids and adults he met along the way. Last week, he sat down with Oprah.com to explain how each of us can pitch in in large, measurable ways—without quitting our jobs, giving up everything we own and moving across the ocean.

1. Start with Your Own Family

So many of us think that we have to go out into the world to serve, but as we search for that nearby soup kitchen or nursing home, we forget how many isolated, needy members of society exist in our immediate circle. Is there a nephew in your life without anyone to take him to (or pay for) his school? Is there an elderly aunt whose car needs an oil change? Compassion, says Ziolkowski, isn't just for strangers.

2. Rethink Your Birthday

We all want to volunteer regularly, but when our calendars start exploding with to-dos, we often forget to schedule the hours—or can't even find them. Instead, consider celebrating your birthday with eight hours of service. It's easy to remember; whether you like it or not, that particular day happens without fail.

The idea, Ziolkowski credits to Rayia Gaddy, a teenager in his Detroit after-school program. Three weeks before her 15th birthday, Gaddy's big brother Vandel was killed, shot in the back by an AK-47; she was devastated. "She couldn't talk to people," he says, "She couldn't come out of her room." When her birthday arrived, she knew she didn't want to throw a party. Instead, she headed to a homeless shelter for veterans and spent the day serving meals and playing board games, an eight-hour stretch that inspired her to become a permanent helper at the facility. How many of us moan and groan about our own birthdays? What if, instead, it was the day that most inspired you? In Gaddy's case, that one "celebration" prompted her to complete 700 hours of life-changing work...while she was still in high school.

Next: When it pays to get emotional

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