If you're flaring too early, there are a few good tips and drills you can do with your instructor.
1) Practice doing "soft field landings", or a modification of one. Have you been taught them yet? If not, ask your instructor about them. The main thing in s.f. landing is that you keep a trickle of power on right down to the touchdown.
With a trickle of power or .. a bit more than power than that, you just keep flying the plane along the runway lower and lower until ... well you land.
The same principle is used for normal landings (power to idle at threshold).
(For light prop airplanes anyway ... which is what we're talking about here).
While doing the s.f. landings, pay attention the "sight picture" of what "100Ft, 50ft ." above the ground looks like. Next time you takeoff, also try to be aware of the same sight picture ... or have your instructor do the takeoff, while you just watch how the surrounding picture changes.
A great analogy an instructor showed me, is ... : stand up beside a table top, then gradually sink / squat down while lookiing at the table top and observe how it "flattens out" as you get lower. Same thing happens while descending in a plane.
2) Similar to the s.f. landings, is to just descend and then fly along the runway at normal cruise power at ~10-50 feet up to, get accustomed to the sight picture. If you get down to around ~5 feet you can just convert that to a landing by reducing the power to idle.
The main thing about the flare is that you have to react to the current sink rate of the plane. Initially, you just want to level off the plane from it's nose down attitude. That will greatly reduce the sink rate. From there, pay attention to the sink rate and your AIR SPEED and your height above the ground. As the plane wants to sink, *gently* counter-act the sinking with more nose up ... with the maximum being ~ the nose of the airplane on the end of the runway ... very much ...if not identical to how it will look when you take off. If you're still sinking fast with the nose on the runway, ADD POWER !! don't yank back any further on the wheel !
And if you're totally messed up ... GO AROUND !
Also, I'm in the 50% camp that thinks flight simulator software is a great help when learning to land. Get MS fliight sim or Xplane ..etc and practice landings and look at the sight picture of the runway "flattening out" as I described.
The most important thing to remember is to keep flying the plane. It's not going to "stop instantly" at your touch down point. Flare at ~10-20 feet and just keep flying it until it doesn't want to fly anymore and you should be getting you first "greaser" soon.
Mike