As alluded to above, many who do or did commute to London find all sorts of methods and ways that turn out to be quicker (or only marginally slower but significantly less stressful), despite not being offered by whatever "journey planner" is being used.
Depending on how much quicker than Google you are, if you're loosing time on your public transport journey, Google maps suggests a 32 minute walk between Chancery Lane and Waterloo - experience tells me that's about 25 minutes at my pace. Similarly, if needing to circulate via Victoria, how about walking to Temple, then using the District and Circle? Or walking to Holborn, then using the Piccadilly and changing at Green Park?
In my experience, the best way was to find a method, hone it well, and stick to it.