If you haven't read the Introduction to the Devout Life by St. Francis De Sales, I recommend you do - one of my favorites. Here is the paragraph I really liked:
"Certainly nothing can so effectively humble us before God's mercy as the multitude of his benefits and nothing can so deeply humble us before his justice as our countless offenses against him. Let us consider what he has done for us and what we have done against him, and as we reflect on our sins one by one let us also consider the graces one by one. There is no need to fear that knowledge of his gifts will make us proud if only we remember this truth, that none of the good in us comes from ourselves. Do mules stop being dull, disgusting beasts simply because they are laden with a prince's precious, perfumed goods?"
Humility: Knowing first that you are a dull, disgusting beast laden with a prince's precious perfumed goods, and second that God has a really huge soft spot for dull, disgusting beasts.