It all started when I was pregnant with Cole. I observed a friend diapering a three year old who had jumped pooped in his diaper. The kid to me looked huge and so did the poop, there and then I vowed I would do my best not to have to do this with my little one. This vow unlike the one I made to not have a screaming kid in the store, was one I kept.
With early training it is a process not a three day event. At about a year and a half introduce the potty to your child. I had one little potty bought at Wal Mart for $8(it doubled as a stool) that Cole sat on when he was an itty bitty. Cecily never used this until she was completely trained and observed an older friend using it. I have since "dumped" the potty, it grosses me out. Another tip is to select a time each day to put your child on the toilet. If they do not wake up really wet, first thing in the morning may be a wise choice or at night before bath. You want your toddler to just get used to the idea. My children both sat on the adult toilet backwards, it gave them more stability and then they were not hooked on a seat that was not with us at all times. If you sit them many times with no luck, still praise and praise them. After a while if there is still no toileting, think about helping them along. One way is to simply turn on the faucet and another option is to use a cup of warm (not hot) water. Sometimes that splash helps them on the way.
Once your child begins to occasionally have success, you can move on to trying to go with no diapers at home. I leave my children naked from the waist down and give reminders or take them in the early stages. If they resist you then STOP! Do not force this issue or it may backfire. I have used the occasional M and M but praise and a quirky potty song works just as well. Summer is the perfect time for this as long as your neighbors do not think your nuts for having a half naked kid prancing around.
Successful early potty training is a process that involves, patience, praise and a willing participant, It is not about training the parent so if it feel like you are doing all the work, wait another month and give it another go. Also success is awake dryness, you will often still need diapers for nap and night. This is not a game of all or nothing.
For me Cole was trained the week he turned 2, but I kept him in a pull up months after when I sent him to the nursery or we went on long car rides. He did not fully night train till he was 3.
Cecily was a "whiz" and was in underwear at 20 months. I still throw a diaper on her some nights but the accidents at night are very rare. I bought my last pack of diapers in March and it felt great. If you have questions please ask, but I remind you this is just what worked for me kids and may not be the answer for you.