Inorganic solid electrolyte materials have great potential to overcome the issues of conventionally used organic liquid electrolyte materials in lithium ion batteries. Garnet-structured Li$_7$La$_3$Zr$_2$O$_{12}$ based solid electrolyte materials having high ionic conductivity, good thermal and electrochemical stability and most importantly excellent stability with respect to lithium metal anode seems to be the most promising candidate to be applied in all solid-state lithium ion batteries. Garnet-structured electrolyte materials synthesized by conventional solid-state reaction method requires intermittent grinding and calcination steps along with sufficiently high temperature and long time for sintering. A significant amount of lithium is lost during this lengthy synthesis process, resulting in lower ionic conductivity and bulk density. Since these two factors play the most important role in the performance of an electrolyte, therefore, some other synthesis methods are required, which help in enhancing the performance of Li$_7$La$_3$Zr$_2$O$_{12}$ based electrolytes and also are easy to operate, ecofriendly and cost effective. Here an overview of the various synthesis methods has been provided and their feasibility for Li$_7$La$_3$Zr$_2$O$_{12}$ based solid electrolyte material preparation, in the context of their ionic conductivity enhancement and commercial applicability have been reviewed.