Several methods of increasing the thrust and energy efficiency of charged particle jet engines operating in a gaseous or liquid medium have been developed. We identify the three main components of charged particle thrust generation and show how to take maximum advantage of each. We also describe several structures and techniques to reduce the energy associated with the generation of charged particles and to minimize the number of charged particles needed to further increase energy efficiency. In addition to the structures and techniques used to increase thrust and energy efficiency, we have also developed several structures and techniques for efficiently controlling the amount and direction of thrust. Finally, we show many uses of these charged particle jet engines and ways to control them.