zoti,

You need to practice landing can be tricky and different types of planes can require different landing approaches (no pun intented).

Basicly you control your decent rate with the throtle throughout the glide slope
and you control your air speed with the elevator.

What I do with each new plane I get is go up to mistakes high (100-150 ft) and practice landing the plane to familarize myself with its glide and stall characterics.
With trainer type planes I have found that 75ft and 1/2 throtle going into base and then losing 25ft to make the plane be at 50ft altitude and idle going into final approach with the start of final being (125-175 yards from the end of the runnway) puts the plane at 3-7ft as it crosses the threshold and touch down is usually in the first third of runway(50-400ft) agian if you are decending to rapidly (due to model type or wind conditions increase throtle to maintain altitude)

I may not have explained it clearly its something that just kinda clicks with you after a lot of practice