The story of Bartimaeus in chapter 10 of Mark's Gospel was one that I used often during retreat.
It describes Bartimaeus as a blind beggar, and that's what we all are before God. Bartimaeus simply kept on shouting out, "Jesus, Son of David, have pity on me!" When the people around him tried to make him stop, he just kept shouting louder. The Gospel says a large crowd of people were following Jesus. I can imagine them walking along the dusty road, under the burning sun, pushing and shoving, all trying to get to Jesus. But Jesus stopped and stood still because he heard Bartimaeus.
It reminds me of the scene in March of the Penguins when the father penguins return and pick out their chick from thousands of them, just by the sound of its voice. Jesus listened to Bartimaeus despite the large crowd.
Bartimaeus is a great model of prayer because he knew how to ask!