Reviewed by Sarah Pearson, M.D., August 2006

To make potty training as smooth a process as possible for you and your preschooler, take a moment to learn about not only what works, but what doesn't:

Starting too soon

Starting potty training before your preschooler is ready will only make it more difficult and prolong the process. There's no magic time when it's right to begin, though most children can get the hang of potty training by age 3 or 4. Keep an eye out for physical, cognitive, and behavioral signs that your child is set to give it a try.

It may take up to three months to potty-train your child, and it's important to be patient and supportive throughout. If you've been trying for three months without success, your child may not be ready — wait a few weeks and try again.

Starting at the wrong time

It's not a good idea to begin training a week before the new baby is due, when you're changing caregivers, or during any other disruptive time in your preschooler's life. Young children are creatures of routine, and any changes to the usual program are likely to cause setbacks. So wait until things have settled down before you start.

Putting on the pressure

If your preschooler has started to show an interest in potty training, that's great. But don't push him to get through it faster than he's able. If he gets nervous, he could start holding in his stool, which can lead to constipation and other problems.

Let him take his time and get used to this new, multipart process step by step. He'll move from one stage to the next at his own speed. It's fine to try to motivate with gentle reminders and encouragement, but if he balks, don't push it.

Leaving too much up to your child

Although your child's getting more and more independent all the time, you still can't assume he'll take the initiative to get to the potty when he needs to go. Kids this age often get so absorbed in what they're doing, they'd rather "hold it in" than stop their playing. Holding in pee often ends in pants-wetting, and holding in poop can lead to constipation, which in turn can complicate potty training.

So stay involved in the picture and make sure your child takes regular trips to the bathroom during the day, even if he says nothing will come out. Feed him a diet high in liquids and fiber to keep things moving through.

Punishing your child

It won't accomplish a thing to get angry or penalize your preschooler if he's not interested in training, won't sit on the potty, has an accident, or has any of the other common problems kids have while potty training. Setbacks are natural, and scolding will only make him less interested in training — he'll be afraid any mistakes will upset you. If you can, respond to messes and other challenges calmly — and if you can't, bite your tongue and count to ten, then try again. Should you start to get truly anxious about your child's progress, give his pediatrician a call.