I like this post on Motivating Kids to Do Their Best from MVParents
Here is Lynett's intro, "You want your kids to do their best. But what is their best? How do you know if your kids are living up to their full potential? Consider these ideas."
And here is a sampling of her ideas - there are many more in her full article:
Notice how much your child is self-motivated. Some kids seem to know what they want and go after it. Others seem to dillydally a lot. Every child has a different amount of self-motivation.
Be aware of the difference between extrinsic motivation (being motivated by others with rewards and bribes) and intrinsic motivation (being motivated internally to do something). Although it’s okay to try to motivate kids from time to time with rewards, try to get in touch with what makes your child motivated from the inside and focus on that motivation.
Look for fun ways to spice up activities that your child doesn’t enjoy, such as certain chores or doing homework for least-favorite subjects. For example, play music and dance while you dust. Or let your child sit with a favorite stuffed animal while doing homework.
For parents with children ages birth to 5
A key point for this age group is to give kids stimulating activities that encourage their curiosity—rather than kills it. Kindergarten teachers say they can always tell which kids have had their curiosity nurtured when they arrive at school the first day. These are the kids who have had parents who take them to interesting places (zoos, children’s museums, the library, the playground, the grocery store) and also have provided interesting, stimulating activities, such as reading aloud, going for walks and identifying colors, and building towers out of blocks.
For parents with children ages 6 - 9
Young children are still highly relational. They tend to be motivated to do well when they adore the adults they’re with. Connect them with trusted, competent adults who care about them.
For parents with children ages 10 - 15
Notice the new interests that get your kids excited. Sometimes it’s giggling about the opposite sex, reading comic books, or fashion. Kids at this age are highly aware of which social groups they fit into and don’t fit into, and so many are motivated to look—and act—a certain way.
For parents with children ages 16 - 18
Keep tabs on how competition is affecting your teenager’s motivation. For some teenagers, competition motivates them more. For others, competition paralyzes them. Give suggestions on how to handle competition well.