With the rapidly progressing world in the field of manufacturing, non-conventional machining still requires numerous advances. The requirement of machining a material with Brinell hardness greater than 200 BHN with utmost precision and intricate geometric features is catered, to some extent, by Wire Electric Discharge Machining (WEDM). WEDM is a non-conventional electro-thermal contactless machining process in which the cutting operation involves a thin strand of metallic wire with pulsating current flowing through to create a spark between workpiece and wire. The complexity of this operation demands countless input parameters to be optimized to produce the best possible results. Various techniques have been used by researchers for this purpose. This paper reviews five such techniques of optimization including Taguchi Technique, Design Of Experiments (DOE), Response Surface Methodology (RSM), Genetic Algorithm (GA) and a combination of different techniques. Furthermore, an analysis is provided for the best three approaches for each technique. This paper also discusses an in-depth knowledge of the applications of these techniques along with the process flow diagram to summarize the process.