Bettas are pretty smart too, I feed mine at the same corner of the tank each time (both tanks of bettas). As soon as they see my fingers near the water (I also feed pellets), they rush over and wait for me to drop it. I drop it about an inch away from their faces so they can see it, and I only feed one pellet at a time. Gives me some sort of control over how much they are eating, so there is little to no waste. If they don't eat the last one I drop in, only one is wasted. And that one usually gets picked up by the filter.
As for bloodworms, I thaw mine in hot water in a cup and pull one worm out at a time with a toothpick. If you dangle it just barely in the water and move it around, they snap at it like bass. I'm "fishing" in my own tank...hehehe. They don't eat many bloodworms, maybe 2-3 a piece, and the rest I dump into my hatchling turtle tank, who eats them like a pig. If you don't have something else to eat them, the method of cutting the frozen block into pieces is a good idea. The large frozen blocks of bloodworms hold A Lot of frozen larvae.