Round out and flare vary each landing and type of aircraft. Typically though you have to know in your screen where your aim point should be on a normal day. From there monitor the trends; getting fast, slow, high, low, etc.

This can be debated for another 100 years of aviation but pitch for A/S, power for glidepath or pitch for glidepath, power for A/S technique can be the root of some problems in the flare.

I teach folks who have problems with energy management on final to adjust the pitch to continue to the aim point. If you are getting fast you're high, start a fwd slip. If you are holding the nose on the aim point and getting slow start adding power.

There are many other variables to this technique but this is it in its simple format.

With this technique though you will tend to find that your aim point will start to move under the nose of most light GA aircraft at about the same altitude above the ground everytime, i.e. when you are approximately 10' AGL and need to start rounding out.

At this point hold straight and level until you begin to sink. If you are still sinking after the rounding out begin the flare. I've found over the years that students are nervous about "squeezing back" too much to flare and then flat on touchdown.

I have students who have problems with control pressure in the flare go and fly numerous power off stalls. While inducing the buffet I have them simply set the nose on the horizon and keep it there constantly adjusting pitch control pressure to do this as the airspeed bleeds off.

This helps them quite a bit on realizing how to contiously adjust their pitch in the flare to not balloon and to hold the airplane off the runway for smooth touchdowns but also how long they can hold the flare attitude until the buffet arrives.

I've taken this technique and went from some of the unsafest roundout and flares to next pattern ride greasing them on all day long.

Hope it helps.