Around age 2 is a reasonable time to start thinking about it. Children may show their readiness by signaling their parents every time they need a diaper change. Dr. White suggests beginning the process by making a potty chair available to the child. The chair should be small enough for the child's feet to rest on the floor while sitting on it. After the child gets used to seeing the chair, he suggests inviting the child to sit on it occasionally, with the diaper either on or off, and telling him what it's for.
Books also are available to help children grasp the concept.
Parents should reinforce successes with lots of praise, and perhaps even special treats. But if children resist potty-training, parents shouldn't punish, scold or ridicule. Flaring tempers and frustration, he said, will only hinder a child's progress. And even when things are going smoothly, expect some fits and starts. For instance, children who urinate regularly in the toilet may be reluctant to have a bowel movement anywhere but in a diaper.