I think what your teacher means is not to try to play by ear so much. Playing by ear and memorizing are good, but you also need to be able to play from a sheet without concentrating so much on the keys. It does take a lot of practice to know where things are underneath your fingers, and like people have said, for bigger jumps pretty much everyone has to look at their hands. But I think the aim here is to be able to sightread better, and stumble a little less.
And I probably just repeated what a bunch of other people said -shrug- sorry about that.
And I probably just repeated what a bunch of other people said -shrug- sorry about that.