Meditation
The Eight used meditation in order to suppress the voices of his previous incarnations, (AUDIO: The Eighth Piece, The Doomsday Chronometer) as did the Nine following his regeneration. (AUDIO: The Crucible of Souls) The Twelfth Doctor tried meditation in 1138 Essex for three hours before he got bored. (TV: The Doctor's Meditation)
Susan Foreman practiced meditation, able to slow her pulse enough that she seemed dead to the outside world. When she met Anastasia Romanov, she thought the princess this technique, hoping that the human might have used it to stimulate her death and escape her historical death sentence. (AUDIO: Last of the Romanovs)