Hand-washing is one of the best defenses against winter colds and flu. But it's not always at top of kids' to-do lists.

Here's some advice to get them to soap up:

• Be a good role model: "Wash your hands when you expect them to wash their hands," says Terri Khonsari, an industrial psychologist and author of "Raising a Superstar." "Children learn from what they see more than what they are told."

• Make hand washing your mantra. Stacey Kannenberg, author of the "Let's Get Ready Series," children's books that prepare kids for kindergarten and first grade, tells her daughters, 6 and 8, to wash their hands over and over in a sing-songy voice.

• Make it fun. Sing with your children while they wash their hands. Use fun soap, such as SquidSoap, which stamps a child's hand with vetegable dye and doesn't come off until 20 seconds of washing. Tell them to teach handwashing to their dolls, says Khonsari.

• Tell them why it's important to wash their hands. Make it a topic at the dinner table. Mary Jo Finley, a mother of two in San Diego, tells her children "that there are bugs you can't see and you need to wash them off so you don't get sick."

• Buy step stools for the sinks. Kids like the idea of stepping up on something.

And here are the keys to handwashing that will work, according to Dr. Marian Michaels, an infectious disease specialist at Children's Hospital of Pittsburgh:

• Do wash for 20 seconds — or longer. A good guideline for children is the time it takes for them to sing their ABCs.

• Don't use really hot water. Hot water can chap hands, which can increase risk for infections.

• Don't use anti-bacterial soap unless you are at an increased risk for a skin infection.

• Keep nails clean and short. Use a nail brush to clean under the nail.

• Hand sanitizer is a great alternative. But if there are particles of dirt on your hands, it's better to use soap and water.