I have to thank my son, age two and calling himself "Um" at the time, for the title to this post. I was listing his friends, attempting to invoke a little peer pressure, "Jay's potty trained and Amy's potty trained, and Sam is potty trained...". To which he answered, "Um wants to be on the potty train!"
And so he did board, one month before his third birthday. Not because he had a ticket, but because I ran out of diapers the night before Thanksgiving. There was just no way on earth I was going to enter a store the day before Thanksgiving for a child who could already change his own diapers. I'd like to say it was some kind of awesome parenting on my part that I can count his total "accidents" on one hand, but I'm pretty sure it was more of a fluke.
In any case, between my own two kids and five years of teaching preschool, I figure I can technically claim to have been potty training children for seven (albeit nonconsecutive) years. I've noticed a few things and occasionally give out advice, including the following:
The biggest and most typical problem parents face is power struggle. If and when kids figure out that you have a vested emotional interest in one of the few areas of their lives they can control, you're in big trouble. Nothing delays potty training like a child noticing their bodily functions are a constant topic of conversation. If you feel anger or find the topic taking up more than its fair share of your gray matter, it's time to take a step back and try again in a few weeks or a month. It's their poop and children WILL win if they decide to dig in those heels.
Pull-ups: more expensive yet less convenient than diapers. I can almost guarantee that your child's preschool teacher wishes your family would skip this step. The toddlers and preschoolers are evidentially not watching enough Pull Ups commercials to realize that fancy expensive diapers are supposed to make them feel like big kids. The preschool teachers treat them just like diapers, except that if a child poops, teachers are likely to have to remove their pants, shoes, and socks instead of just a diaper.
When to switch to underwear: when your child has some control and you have some patience. Most parents know the physical signs of readiness on the part of the child. The only thing I want to add is that it is just as necessary for the adults to be emotionally ready. Make friends with the washing machine first and foremost and try saying "Oops! We'll have to wash that!" with as little rancor as possible a few times before you even begin.
When to switch to underwear at preschool: After your child has been successful for a week or two at home, he or she is ready to come to preschool sporting underwear. Children are successful sooner in their comfort zone, so it makes the most sense to start at home.
Sitting or standing? If you're the one who has to clean the toilet...well, let's just say I know a women who asks not only her boys but also her husband to sit. At my preschool we have child sized toilets not to mention janitors, so it really and truly makes no difference. At home you might want to consider whether your child is tall enough to stand and how stable he feels if he does stand on a stool.
Fear: I have a child afraid of the potty almost every year. There's the precarious position, the scary sound, the water which looks much deeper to a child who may not be able to swim. I've had a parent ask me every year if I think their child is afraid because he or she has been traumatized or is suffering somehow. To me chances seem slim. The potty can just be a scary place. Try offering to flush after your child has left the bathroom.
Bribery: This is supposed to be a no-no, but y'know, sometimes it works. Smaller bribes seem to work on occasion, but the more successful bribes usually go something like, "You'll get a huge kitchen set for Christmas if you poop in the potty." It's winds up escalating what is probably already a power struggle, but if you have the means and your kids aren't that stubborn, maybe it's for you.
With just a small change in semantics, bribery can turn to the Premack principle, otherwise known as "grandma's rule", a perfectly acceptable form of parenting. This is the ole' "As soon as ______ happens, _______ will happen."
Bribery: If you clean up your toys, I'll take you to the park.
Premack principle: As soon as you're done picking up your toys, we can go to the park!
Bribery: If you poop on the potty, I'll give you a cookie.
Premack principle: After you sit on the potty, you can have a cookie."
See how the Premack principle assumes that mission will be accomplished while the bribery sort of has an element of begging? Done with the consistency and without negative emotion, the Premack principle can be a friend in more areas than just toileting, as opposed to bribery which will always feel like bribery.
Note that "You can't go to the park unless you pick up your toys!" or "You can't have a cookie unless you poop on the potty!" turns the situation away from presumed compliance and back toward coerciveness.
One family who had been involved in a power struggle of rediculous proportions had their problem solved when summer came around. I'm not sure if dad presented this using the Premack principle or if it was more of a natural consequences type thing. After months of struggle, Joey was potty trained seemingly overnight when told that the local pool did not let children swim in diapers.
Of course you want to ask your pediatrician if things seem to have gone awry, but generally the more relaxed you are about potty training, the better it will go. So to speak. Good luck!