How to teach a child to ride a bike
Let me start out by saying that I was not taught this way, but I wish I was. I was taught in a community college parking lot by my parents, and while there are many things I thank them for -- teaching me to ride was certainly one of the most memorable.
At the same time, the way I learned was more of a crash course.= The best way to teach a child to ride a bike, is to take off their pedals and lower their seat so that their flat feet can touch the ground Have them "walk it" around and after a couple weeks they will have gained the necessary balance. After all the first bicycles didn't have pedals. Once they are ready put their pedals back on.
If you're working with a child who's a little bit older and doesn't know how to ride a bike, or is intimidated or embarrassed by their friends who can ride, start them off not on a bike, but on a two wheeled scooter. Either the newer "Razor" type scooter or the inflatable tired type will work. The balance and turning/leaning work the same on a scooter as they do on a bicycle, and the scooters can be less intimidating to learn, as the child or adult won't be as intimidated trying to figure out what to do with their feet as they move forward, and can focus on the turning/leaning/balancing which makes riding a bike possible.
If you really love your child, get them a helmet -- how is that for guilt? If that doesn't work, consider the fact it is illegal in most places for them not to have a helmet and you will pay the fine!