I recently taught my wife to ride a bike. She was 42, and had never done it. This is how I did it.
I got a bike that is way too small for her. I put the seat all of the way down, and I took off the pedals. I had her use it as a scooter for a couple of hours. She could scoot around the parking lot pretty good after about 2 hours. She got so she could lift up both feet and coast for quite a ways. Then we stopped for the day.
Day two, we did the same thing again for about 45 minutes. Then I raised the seat a little bit, and put the pedals on. Learing to pedal was easy, because she had a good feel for balance and steering.
It may be embarrassing to try, but it really worked. Now she rides everywhere!!!