I realized one day that although our kids each have a stool to reach the sinks in the bathroom, they still aren't tall enough to see themselves in the mirror.   I decided to buy small mirrors we could mount much lower for them.  

After searching everywhere for a small, simple mirror and not being able to find one small enough, I got the bright idea to look in the section of the store where candles are sold.  Sure enough, while in Walmart I found the perfect size mirror.  There were several shapes and sizes so you can adapt it to the space you have.   I then went over to the hardware section and got 4 mirror mounting brackets.

My kids can now see and do a better job brushing their teeth, washing their faces, and are really getting into flossing by themselves as well.