"True humility is not thinking less of yourself; it is thinking of yourself less." (Rick Warren’s The Purpose-Driven Life)

based on cumulated lectures by C.S. Lewis published by the BBC as "Mere Christianity"

"Do not imagine that if you meet a really humble man he will be what most people call ‘humble’ nowadays: he will not be a sort of greasy, smarmy person, who is always telling you that, of course, he is nobody. Probably all you will think about him is that he seemed a cheerful, intelligent chap who took a real interest in what you said to him. If you do dislike him it will be because you feel a little envious of anyone who seems to enjoy life so easily. He will not be thinking about humility: he will not be thinking about himself at all.

If anyone would like to acquire humility, I can, I think, tell him the first step. The first step is to realise that one is proud. And a biggish step, too. At least, nothing whatever can be done before it. If you think you are not conceited, it means you are very conceited indeed" (C.S. Lewis, "Mere Christianity", Book 3, Chapter 8, “The Great Sin”)