What to do if the induction doesn't work

I learned hypnosis from a very good teacher, and prior to exiting his class I had successfully hypnotized several people (including a few randoms in a mall). Anyways, i went back home and was able successfully hypnotize several more people, but I eventually stopped. The reason, was that I increasingly found friens and family members for whom I was not able to produce phenomena. I was unable to get the compliance from them that I had gotten from others. Even worse, every time I screwed up an induction, they became convinced that they were unable to be hypnotized and I was never able to hypnotize any of them.

To all of you, what do you do when your inductions don't work? How can I expand my toolbox so that I run into this problem a lot less.