The amount you feed will greatly depend on what type of fish you keep.
My marine betta, only really needs food a couple of times a week, as where my anthias need heaps more two three times a day, m trigger needs heaps of chunky/meaty food, other wise he just goes skinny.
I think small amount more often is the best way, well works better for me.
Say small pinch of dry food, couple of hours later cube of frozen etc, up to 4 times a day, this is what i do.