Instead of feeding one or two large meals a day, split that evenly into smaller portions, 3-4 times per day. It's not about grossly overfeeding, but feeding smaller meals several or more times in order for the fish to best utilize the nutrients in food as well as increasing their metabolism. Obviously, you can't always be there to consistently feed them throughout the day, so I would recommend using a good quality auto-feeder, like Eheim.
Another important factor in growth is water quality, which is directly related to amount of space. Adequate space and lots of clean water (i.e., large water changes) should help in fish growth.
With my Malawian most would decide they were full when they were full. Feeding live and dried tubiflex would get them to push themselves. They would get plump but nothign ridiculous.
The ones I suspect were bumble bee cichlids, would not get full. I referred to them as "tootsie fish" as they were round like tootsie rolls. They couldn't eat themselves to death but they could eat to the point they no longer looked like fish.
Is there a special reason you want to powerfeed? Some fish are quite tolerant of it/love it, others it can be damaging/fatal (Alas poor betta, I knew the well...).
If you want to powerfeed I assume you are looking at Malawian or Victorian and not Tanginikian?