Autocycleplane
Cruisin' on my Bluebird
Get a bike that she can sit on with both feet flat on the ground. Remove the crank set and chain ring along with the chain. Have her use it like the velocipedes of the 1870s and just push herself along one foot at a time and every now and then lift both feet off of the ground and coast. This way she will learn balance and can easily put her feel back down if she starts to go off balance. After she has mastered the balance, you can better introduce her to pedaling.
This.
Training wheels are not a good way to teach at all. The Europeans know what's up when teaching kids how to ride a bike - they all start with gliders which is what gtdohn is basically suggesting.