when i was first learning, i found the landing very much the hardest. you can flare too early or too late! the only problem i was having was that i stare at the runway coming towards me and hence cant judge the height correctly. so always look at the far end of the runway to judge height.
also, the plane will land itself so always keep it flying, end of the day, the plane has been designed to fly!
also dont use the instruments to fly!!