When you are trying to lose weight and keep it off, health experts say you need to do two things — decrease your caloric intake and increase your physical activity.

A similar strategy also works when you are trying to lose a lot of debt. You can either decrease your spending or increase your income. Often you have to do both because you can cut only so much.

Getting part-time work was the last major piece of advice I gave the Color of Money Challengers, four people — two single women and one couple — who volunteered to undergo my financial boot camp to achieve their financial New Year's resolutions. This is the latest installment in a series that has followed Carl and Tania Chandler, Carlesa Washington and Annie Schleicher in their quest to pay off thousands of dollars in credit card debt.

At this halfway point, the challengers have all done well. However, they still have to do more to get rid of their debt before the end of the year.

The Chandlers, a Maryland couple, have gotten their credit card debt down to $12,000 from $14,400. Tania, a school counselor, recently changed her work schedule, adding more hours and another $6,000 to the couple's combined $137,000 annual income.

The Chandlers have small children, Myles, 5, and Sydney, 3, so they both can't work second jobs. The extra expense for daycare would largely offset the additional income. However, Carl can earn quite a bit of extra money as a telecommunications consultant. He can install and reprogram telephone systems. That's what he does on his day job.

Washington, a 24-year-old recent college graduate living in the District, doesn't have many expenses. So there's not much to cut. She lives with her mother and doesn't pay rent. Her car is paid off. As I recommended, she dropped the Internet service she gets on her cell phone, which was costing her $20 a month.

Washington, who earns $34,000 a year, has been the most successful of the challengers in making extra money. She spent $595 of her savings at bartending school.

I was a little skeptical when Washington told me about the cost of the training. Far too often people desperate to make money get involved in schemes that only put them further in debt. I would never have approved of the training if Washington couldn't pay for it in cash. In her case, the investment was worth it.

In the last five months, Washington has earned an extra $2,400 bartending at private parties. She landed a job working weekends at a nightclub and expects to pick up an additional $400 a week before taxes.

So far, Washington has used every penny — minus what she's estimated she'll have to pay in taxes — to reduce the $3,725 in credit card debt.

That same motivation has led Schleicher to take on a second job. Schleicher, who earns $44,000 a year, is trying to pay off the remaining $2,800 on her only credit card.

Schleicher, who had been a high school teacher, is now tutoring part-time. She's signed on with an agency that arranges tutoring jobs for her. Because Schleicher got started late in the school year, she's only earned $264 so far. However, once the school year starts, the company wants tutors to work at least four hours a week. At a minimum she could earn $132 each week in extra income, which she plans to use to pay off the credit card debt.

Michelle Singletary writes for The Washington Post. Her e-mail address is singletarym@washpost.com.