How do you fly a TARDIS?

Only four people know how to do that- The Doctor himself, his evil opposite number The Master (the only known other surviving Time Lord to date), Captain Jack Harkness from Torchwood, and The Doctor's daughter River Song. His companions know how to work some of it, but fall way short of being able to pilot it themselves. The TARDIS is also itself a sentient machine with organic origins, and can to some extent think for and fly itself.