Preschoolers learn values best by stories. They love to listen to stories. Who Cried Wolf has been used millions of times over to teach small children about honesty. Many children's stories are expressly written to convey values. As you read to your children, ask them questions that elicit their thinking about the values they hear.
Young children love to hear stories about their parents' childhood.
There are probably stories you could share about how you learned to be honest, kind, or brave. There may be some less favorable stories you may remember as well. Don't brag about the times you got in trouble with your parents or teachers unless you can point out a lesson that you learned. If you brag about your trouble-making times, your children can be expected to try to outdo you, but the shoes will be on different feet, and you may not appreciate the naughtiness you've taught your children. Your children will also be learning values by watching you.