Here has what has worked for me and my kiddos:
Between 2 years 3 months and 2 years 6 months, I potty train. I feel like it is some sort of magic age for learning to go on their own-a window of opportunity so to speak..
I plan ahead when I'm going to start. I make sure it an easy week, and I don't do it right before a vacation or a new baby or any major change. I wait till things are calm and regular.
I get out potties or potty seats. It doesn't matter. I set one in the upstairs and downstairs bathrooms and just let them get used to it. I am introducing it, totally casual.
We go shopping for new undies...I use the thicker trainer kind at first.
I have never used pull ups! Pull ups are the invention of a bunch of diaper executives to extend their profits as long as they can. I try to put myself in my child's place-could I physically tell the difference between a diaper and a pull-up? Then how can I expect my child to? I think they need a change...the sensory aspects that trigger their brain to make them realize...oh boy, here it comes, I don't have a diaper on anymore, I've got to GO! They don't have time to ponder, 'diaper or Pull up or undie'? They also have to feel icky. Feel very wet, or very poopy.
So we are ready to begin. I have diapers for night, but hide them. No more diapers is the die hard rule. NO MORE DIAPERS.
Once diapers are off and those big boy or girl pants are on, that's it. I don't put one on when we go somewhere, take it off at home, back and forth. Too confusing for them.
I keep the child as naked as possible...just undies, or very light easy to pull up or down shorts. They have to see for themselves what happens and why it happens and what it feels like and they have to learn what to do after all those things.
I don't do anything for that week or maybe two weeks if it is taking little longer. If I have to go somewhere, I pack an extra change of clothes, or wait till my husband gets home.
I will change maybe 4-15 undies those first days. (Abbey took 2 days, Andrew took 2 weeks.) I am prepared for major laundry and don't stress out about it. I know I will be doing a load a day during that time.
I TRY TO NEVER EVER GET FRUSTRATED! Yes, it takes major patience. I say, "Oh now you are wet, now we have to change." Maybe I have them sit on the potty right after and explain that they need to put their pee and poop in the potty. Never punish or be angry at a child potty-training-they are learning a new skill and that takes time.
It's amazing from their perspective all that they have to learn. They have to recognize and tie their body and brain feelings all together and then take action. This is all new and they have to make that connection. I don't expect it to be all done in one day or two days. It's a process.
I ask them many many times if they have to go all day long. I have them sit off and on all day if they are willing that first week. If they go-joy! I make a big deal out of it, and we celebrate. Sometimes stickers, charts, rewards work. I think I did those with the first two.
So after they get it during the day, I find that they naturally get it at night too! It will take a couple more weeks than the daytime, that's why I put a diaper on at night. When they wake up with a dry diaper, I know I am done! BUT, I have to be very very careful of the fluid intake in the evening.
Some kids like to go in the big potty...that is the easiest. There are little cushiony rims that make the opening smaller and less scarier. I used those (although everyone else hated having to move it!) with Andrew and he did great. Some others, including boys, used the training potties. I taught all my boys with the "tuck in" method, not the stand up method...it's just too hard at this age...eventually when they are tall enough, they will get it.
If you need more help, I think I developed my method after reading Dr. Sears's Baby Book. Click here for a synapses of what he suggests. It's an excellent article...the weekend method is what I based my training on.