Air taxi Captain reported some SFO taxiway markings and signage were unclear and faded.

Narrative

While operating a Part 135 charter flight in Aircraft X at SFO; we were instructed to taxi from the ramp to Runway 1R. Ground Control issued progressive taxi instructions; however; due to frequency congestion and perceived pressure from the controller to expedite movement; the taxi clearance was delivered rapidly.The airport surface environment at SFO is complex; with numerous closely spaced and angled intersections. Taxiway markings in the area appeared faded and were difficult to distinguish; particularly at high-workload intersections. Signage and painted surface identifiers did not provide clear situational awareness in the moment.While attempting to comply promptly with ATC instructions and maintain flow; we inadvertently taxied onto the incorrect taxiway at one of the intersections. The error was recognized shortly thereafter through cross-checking the airport diagram and outside visual cues. We immediately corrected course and notified Ground Control. No loss of separation or runway incursion occurred.Contributing factors included: Complex taxiway layout at SFO. Faded or unclear taxiway markings. High workload during taxi phase. Congested frequency. Perceived ATC pressure to expedite. Time pressure associated with Part 135 operations. Crew resource management was utilized to identify and correct the deviation promptly. After recognizing uncertainty; we slowed the aircraft and verified position using the airport diagram before proceeding.Human Factors: Time pressure. Communication workload. Expectation bias. Reduced situational awareness due to environmental complexity.Corrective Actions / Recommendations: When operating at complex airports such as SFO; request progressive taxi instructions early and advise ATC if unable to comply promptly. Reduce taxi speed in high-density ramp and intersection areas. If any uncertainty exists; stop the aircraft and clarify position before proceeding. Airport authority should evaluate taxiway marking visibility and signage clarity in the departure areas.