Phil Tagg's methodology for musicological analysis involves several key steps: 1) Selecting an "Analysis Object" (AO) that has broad communication potential. 2) Identifying the musical "Parameters of Expression" and elements in the AO. 3) Finding short meaningful segments called "musemes" within the AO. 4) Comparing the AO to similar "Inter-objective Comparison Materials" (IOCM) to understand collective meanings.