The best way to train it, is to feed at the same time of day, all the time. Eventually, it will basically "learn" that this is when food comes. I don't remember how long it takes, but it will take some time.
I've had mine almost 2 years, and I also feed it every other day. I'm sure feeding it more would help it grow, but this schedule seems to keep it happy. For me, feeding it more often would start to effect my water quality, so I've tried to find a balance between, how much food it needs, and how much I'm "polluting" my water.
Good luck with it!