The root locus technique is a graphical method used in control systems to adjust the locations of closed loop poles by varying system parameters to achieve desired performance. The root locus represents the possible locations of closed loop poles for different values of a parameter in the s-domain, forming a symmetrical plot about the real axis. It has advantages over other methods by being easy to implement and allowing prediction of system performance by indicating important parameters. Construction of the root locus involves 7 steps including finding pole and zero locations, the real axis path, asymptotes, and breakpoints.