Zener is a special kind of diode that is used in voltage regulation. Zener of different voltage ratings are available. Zener requiresa series resistor to drop current across it. See how a Zener based power supply is designed.
Voltage regulation through Fixed Voltage Regulator IC is the most suitable method.78xx series positive and negative regulators are widely used to get fixed voltage to drive loads. Here explains a circuit design to get regulated voltage from a 12 volt 500 mA power supply .This circuit can deliver 5 volts at 300 mA for driving a load. The circuit is Voltage and Current regulated and with Polarity and Surge protection components.