Two versions of a charge injection electrostatic atomizer design, useful for producing charged sprays of highly insulating liquids, have been subjected to systematic changes of their physical and electrical characteristics. The aim is to enhance the atomization of these liquids by maximizing the amount of charge that can be introduced into the spray. Spray current measurements showed that atomizer internal geometry is the key parameter and a "point-plane" geometry was found to be optimum. The "point is the charge injection site, the tip of a needle electrode, coaxial with the "plane," conceptually a disk which contains the atomizer orifice. An important requirement is to place the electrode tip as near as possible to this "plane," while maintaining sufficient current. A ratio of unity of the distance between the tip and the plane, and the orifice diameter, was found to be optimum, and independent of orifice diameter. The orifice length-to-diameter ratio was varied and was found to have little measurable effect on the electrical performance of the atomizer. An investigation of the atomizer electrical characteristics was also performed, by placing large resistances between the metal nozzle body and ground and also placing a ring electrode around the liquid jet as it emerged from the orifice. We found that electrical modifications to the atomizer can provide significant improvements in the spray current and hence the atomization quality.