First practice flying the plane so that it flies level above the runway at your eye height the entire length of your runway.

Get a feel for flying it at this level and what throttle setting you need to maintain to keep it there.

Once you've got this mastered ( it will only take you a half dozen attempts ), fly it down like this to about 1-2 feet high as it crosses the runway.

Hold the plane at this altitude for a second, then cut the thottle to idle and let the plane settle in by itself, while you keep flying it as if you were trying to keep it 1-2 feet high.

That's pretty much it.