I find Jesus' parable on the mustard seed the most helpful.
He told them another parable: "The kingdom of heaven is like a mustard
seed, which a man took and planted in his field. Though it is the
smallest of all your seeds, yet when it grows, it is the largest of
garden plants and becomes a tree, so that the birds of the air come
and perch in its branches." (Matthew 13:31-32)
What I get out of it is this: With one's faith, as with the mustard seed, it takes something from both sides (you and God) for it to grow. There is no clear line of demarcation between your effort and that of God's.
In fact, I find this principle of "no clear demarcation" to be a useful one in understanding the Bible. For example, it also seems to resolve the contradiction between God's will and your own petitionary prayer. In reality, the two need not be mutually exclusive (just like the electron having properties of a particle and a wave, in physics).