DD1 demonstrated that she was totally "able" to use the potty, and we let her lead the way... which meant for most of her second year she was in and out of diapers as she sometimes wanted to use the potty and sometimes didn't. We tried "pushing" (we were in a situation where we might need a temporary daycare situation and they required potty training) a bit and it backfired... thankfully we ended up avoiding the daycare issue. And we backed off potty learning completely.
However, on her third birthday I told her that the diapers were all gone. I spent the next few weeks being very active (in terms of suggesting potty breaks, talking about "listening to your bladder", generally talking about elimination) and doing a lot of laundry (tough with a new babe on the hip). There were a lot of accidents (we called them "surprises" to remove any stigma) and near misses. But I stayed really upbeat and encouraging and totally avoided any suggestion of bringing back the diapers. She turned 3 in early April, by late May the only accidents were at nap time/morning, and there hasn't been a nap/night accident in about a month (knock on wood).
Oh! may not help, but my dd1 always wants to know why we do things. Explaining where urine/feces come from (we chew up the food, it goes down our throat, etc) and WHY it was important to put it in the potty (we have a septic tank, I explained plumbing and explained that the pee/poo goes into the tank and that it feeds the plants/trees/flowers) really got her excited. It did lead to some amusing converstions on her part though... for a while she'd yell out the bathroom window "Hold on trees! I have yummy poop for you!"