Vibration control using piezoelectric materials has been widely investigated over the past decades. Particularly, active controllers achieve greater vibration control over wider frequency ranges than other vibration control techniques. Active controllers make use of sensors, actuators, and control laws. While most researchers focus on improving the control law, investigations on the optimal placement of sensors and actuators remain much less explored. This work presents a simple and quick methodology to obtain the optimal placement of piezoelectric sensors and actuators on different electromechanically coupled systems, without using classical beam or plate structures or limiting assumptions (symmetrical bending, linear strain, etc.). Optimal placement of sensors and actuators is performed based upon two criteria: i) varying the number of piezoelectric layers used for sensing and actuation and ii) varying the position over the structure’s thickness. Each criterion (i and ii) is presented and discussed in a different study case. Results show that as the number of piezoelectric layers increases, vibrations are controlled more efficiently. However, stacking several piezoelectric materials is not easily feasible in practice, leading to a tradeoff between reducing vibrations (using more layers) and ease of assembly. As of criterion ii), optimal placement of piezoelectric sensors and actuators is the farthest possible from the neutral line since sensors generate larger signal output (increased sensor gain), and actuators apply larger momentum on the system reducing more vibrations.