Start when you want to. I have started mine anywhere from 9 months (not intentionally, but she picked up on it, so hey, don't stop!) to 2 years.
Every single child has been different. Since I start mine so early, I just put them on the potty after a nap, after a meal, before and after bedtime. Sometimes I would do that for days or even months until they actually went in the toilet. Then I would praise them and remind them that is what they need to do in the potty. Once they 'got it' I just had to work with them to know when they needed to go.
Incentives: All of mine have been different. One didn't become consistent until he had to take off his wet clothes himself and change into dry (he hated doing it without help), one hated being naked so he got one pair of pants a day. If he wet them - no more. One LOVED treats everytime he went. One loved to change himself - so that didn't work. :)
#1: Be patient!
at 3:38 PM on Nov. 10, 2012