Preschoolers love to laugh. And laughter greases the wheels of serenity and cooperation around the house. To keep things light, keep your own sense of humor about potty accidents and playtime messes. Read silly books together. Listen to CDs of funny storytellers. Act silly yourself to distract your child from a testy situation: "Oh … no … I … have … turned … into … a … monster … who … must … catch … you … and … kiss … you … now!"