There were two tips (both of which I read on here) that helped me out and they still help me out now.
i) As you start to round out, move your focus to about 2/3 of the way down the runway and rely on your peripheral vision to judge the flare. Initially its sounds and feels strange, but it does work.
ii) Someone on here talked about an instructor who used to pull out a £50 note and tell the student it was his if he could keep the aircraft flying just above the runway until the end of the runway. If you try to do this with no power, the only way is to keep raising the nose until eventually you settle onto the runway perfectly.
I hope these help you as much as they did me.