It is more motivating to tell a child they can do something more desirable, “as soon as” they do something you want them to do, rather than to tell them “not until.” An example is to say to the child that you will read them a story as soon as he is under the covers, or that you have something for them to look at as soon as they are fastened into the carseat.
Key idea: Stating a request or directive in a positive manner can increase motivation to comply.