S-turns are used to help cement the basic fundamentals of aircraft control with the goal of developing aircraft control coordination. This is done by flying along a particular ground track at a constant altitude and while this can be tricky the first time around, the maneuver is actually fairly easy if you know what to do.
Hence, a recent post by Patrick Flannigan on AviationChatter.com about performing simple s-turns is well worth reading. In the post, Patrick lists seven steps that might seem complicated at first but its fairly easy if you remember one secret: pick multiple ground references. In other words, connect the dots with your airplane.
Why should you practice doing S-turns? As Patrick noted that its a required maneuver for the Private Pilot checkrides while the Private Pilot Practical Test Standards (PTS) will “require an altitude of +/- 100′ and airspeed +/- 10 knots along with adequate wind-drift correction to maintain constant radius turns.” In other words, its something that every pilot needs to know how to perform.