We recently developed a novel floating-potential dielectrophoretic method to selectively position individual single-walled carbon nanotubes between two floating electrodes while the bundles of nanotubes and impurities were attracted into the region between two control electrodes. In this study, we investigated effects of several process parameters including electric field distribution, electric field frequency, and solution media in order to understand the physical mechanisms of this dielectrophoretic process and to improve its efficiency. Results showed that both the magnitude and the direction of electrical force applied onto the nanotubes can be tailored by changing these process parameters. It was found that a 1 wt% sodium dodecyl sulfate in deionized water is an efficient solution for separating bundles of nanotubes into individual nanotubes and aligning individual nanotubes with a clean surface between two electrical contacts in comparison to N,N-dimethylformamide, 1,2-dichloroethane, 1,2-dichlorobenzene, 1,1-dichloromethane, ethanol, and isopropanol solutions. The fabricated carbon nanotube devices exhibit electronic properties comparable to nanotube transistors and interconnects fabricated by other methods.