zenn,
To share with you, I started toliet train my gal late...when she was ard 21 months.
It took a week for her to understand that peeing has to do it at the potty. I had to bring her to potty every 5-10min, most of the time nothing came out and I ended up having urine puddles on the floor!! It was indeed a tiring and tough week!
Then there's was this one chance when the timing was right and she managed to pee when I brought her to potty. SOmehow my gal able to grasp the concept as straight after this instance, she will indicate to me that she wanted to pee (but not able to control for long, so must quickly rush her to potty).
By the 2nd week, she is able to do it all by herself...go potty on her own (no need to tell her go toilet every 1/2 hr or so), pull down her shorts, sit down on potty, wipe and pull back shorts. Of course, there will still be occasional "accidents".
She started not wearing diapers at night @ 22 months, as I find that she has been dry throughout the night for the past few weeks. But I had to bring her to toilet before going to bed, and sometimes, if I find that she didn't pee much before bed, I will bring her to toilet in the middle of the night - if I happen to wake up.