Remember that your fish lacks a cerebral cortex, so it may be a one-trick pony, and will only be able to do simple ones at best.
Keep in mind the behavior you want to encourage and decide how you wish to encourage it.
As in Pavlov's experiment, use a bell or clicker each time you feed your fish. It is easier to reward behavior with a signal rather than with food.
(With hand-feeding, you need not do this first part, as your RTC will eventually recognize you as the "keeper of kibbles" and just move your hand closer by the day when you feed him, being careful not to scare him.)
Most people will gradually get their fish used to being stroked. You can acci-purpose-dentally brush against him when you clean the tank, or you can touch him deliberately.
Or, this could be an outgrowth of handfeeding your fish...feed, then brush. That's how "Mo" became tame...he associated my hands with food and then tolerated them a little better.
Do it gently, though, and don't spook your fish, or else it will be a long road back to those behaviors which you want to encourage.
Have patience and it will most likely work well for you.
I apologize for not posting this earlier. I am a college student, with a lot of references on my shelf, and studying and class come first...I try to help some people with commonly available references, because they are cheap and somewhat easy to find...I merely wanted to steer you in the right direction, not earn a few extra bucks for Mr. Stratton and TFH, Inc, with whom, again, I have no connection whatsoever.