First, you must fly a good approach. By that, I mean you must have the proper rate of descent, the proper airspeed, the proper flap and throttle settings, wind correction (if necessary), and trim, so that you are not trying to line up the aircraft as you pass the numbers.
Second, you must flare (flare #1) over the numbers. Not necessarily all the way into a nose up position, but enough where you are essentially fly straight and level only a few feet off the ground. Here you want to use your left or right rudder in order to control the heading and maintain the flight path directly parallel and over the centerline.
Third, you want to pull into a nose up position ever so slowly, known as flare #2. If you start to lift off release some of the back pressure, even if this means putting down the nose slightly -- and only for a split second, after which you immediately increase the back pressure, which might feel like the plane is swooping. (You want to land on the main gear, NOT the nose. If you land on the nose wheel or on all three simultaneously, you run the risk of having a propeller strike or damaging the shimmy damper.)
Lastly, use your peripheral vision and also look over the nose to see the centerline. By combining those two actions you get both an idea of how high you are off the ground (so you know how to adjust the flare) and a sense of where you are in relation to the runway centerline.
Above, I have summed up what is necessary; below you can see the animated summation.
My description here just explains a typical landing, but you will also want to be prepared for any and all emergencies. In order to set yourself in a good position for landing, use the "GUMPS" check list:
Gauges are good | Which gauges are functioning |
Undercarriage is down | (You want the gear out) |
Mixture is set to rich | (This prepares your plane for climbing out in the case of a go-around) |
Propeller full forward | (You want to descend) |
Seats and seat belts fastened | (You don't want to bump your head into the ceiling) |