Proportional scintillation in liquid xenon has a promising application in the field of direct dark matter detection, potentially allowing for simpler, more sensitive detectors. However, knowledge of the basic properties of the phenomenon as well as guidelines for its practical use are currently limited. We report here on measurements of proportional scintillation light emitted in liquid xenon around thin wires. The maximum proportional scintillation gain of 287 sub(-75) super(+97) photons per drift electron was obtained using 10 mum diameter gold plated tungsten wire. The thresholds for electron multiplication and proportional scintillation are measured as 725 sub(-139) super(+48) and 412 sub(-133) super(+10) kV/cm, respectively. The threshold for proportional scintillation is in good agreement with a previously published result, while the electron multiplication threshold represents a novel measurement. A complete set of parameters for the practical use of the electron multiplication and proportional scintillation processes in liquid xenon was also obtained for the first time.