When Laurel was about 18 months old she started expressing an interest in the potty. She would come to the bathroom every time Tim, her nanny or I went and she would tell us when she wet or dirtied her diaper. I knew that potty-interest is pretty normal for that age, but I still wondered if we could take advantage of it to start introducing how to use the potty.
It was suggested to me that I try reading the book Diaper Free Before 3 to get some ideas about what to do. The author was a big advocate of very early introduction and gradual teaching of potty skills (starting before a year old). She advised buying small potties and putting them in your bathrooms and initially just sitting the child on the potty once or twice a day. During that time we would read/sing/play with her and keep everything very low pressure (no bribing or scolding or over-the-top praising.)
Once she went a few times while on the potty, we started sitting her on it more and more. Most of the time she really enjoyed sitting there (even if she didn't use the potty) but occasionally it would backfire and she would refuse. At those times we just backed off and tried again later.
By the time she was about 20 months old we started letting her wear training pants/underwear around our house and her grandparents' houses. She had a lot of accidents at first, but the feeling of wetness in her underwear and having to change clothes was a much bigger chore now than it had been before with diapers. (We've used cloth diapers since she was three months old and I do feel that those may have contributed to her early association of going pee-pee equals being wet because there is a little more wetness against the skin with cloth versus disposable.)
We still used diapers for car trips or any outings away from our home or her grandparents' homes and during nap/night time (we still use diapers for sleeping). After she turned two I started thinking more about the book and how the author talked about completely taking away diapers once the child really seemed to know what was going on and could communicate their potty needs. It was a very scary thought, but Laurel was smart enough to know she was getting a diaper to go bye-bye and lots of times she would wait until the diaper was on to go to the bathroom.
Last Friday (Feb. 18) we stopped using diapers completely except for sleeping. And you know what, it's working! Yes, she has an accident once every 2-3 days, but she is going to the bathroom on the potty now not only at home but at restaurants, stores, church, etc. (We use a potty ring on top of a big toilet for public bathrooms.) She is articulating to us when she needs to go without us constantly asking. In fact, her telling us when she needs to go works a lot better because when we try to make her go there's often a power struggles that results with her intentionally holding it and then having an accident once we leave the bathroom.
Since we took away the diapers (and yes, she had plenty of warning) we continually reinforce that she'll need to at least try to go every time we leave the house and before taking a nap or going to bed at night. In lots of different ways, Laurel responds very well to being forewarned of our expectations and as long as she knows what to expect, she rarely argues or resists. This has been the key with getting her to go to the bathroom away from home and when we are leaving our house.
I am not naive enough to believe that she is fully potty trained or that we won't have accidents and possibly regressions, especially with the baby on the way. However, I think all this work on the front end will ultimately result in her complete independence from diapers at a much earlier age than if we just left it all up to her.