You'll find different answers to your question as with experience you have the whole picture and you continue to fly precisely while looking in and out. Good pilots are unconsciously competent. Initially it would help to maintain with the PAPI and look at the R/w as a whole maintaining centerline, thinking that you will fly at a very low level over the R/w touch down point, so as to remember to flare at the right time. The audio call outs are of a good help too, you know your rate of sink by how fast or slow the calls are. Do not attempt to float in order to make smooth landings, as there is nothing more useless than a R/W behind you. Do not delay the power after the retard call and keep flying the aircraft, as the landing is not over until the aircraft comes to a full stop.