I think that growth, and I'm thinking particularly about introverts but it's also applicable to everyone, involves movement in two directions. The first direction is inward and downward, and it involves learning how to embrace and refine your gifts and strengths. For introverts this might involve coming to terms with things like your need for solitude, the tendency to have deeper relationships with fewer people, and your reflective nature. Then it is a matter of learning how to utilize such tendencies better - perhaps learning how to use your reflective side in creative ways - such as writing, or in ways that draw you closer to God - like contemplative prayer, which is a style of prayer which allows God to determine the agenda.
The second direction is outwards, actually moving in the opposite direction that some of your natural tendencies would want you to go. I'm thinking here especially about the importance of community. As much as I would love to hole up in my study, reading, writing, and reflecting 8-12 hours a day, I can't find any mature Christian, of this age or previous ages, who says that you can be a truly mature person without bumping up against other people on a regular basis. Ronald Rollheiser, in The Shattered Lantern, says that one of the time-honored ways to find God in a culture that seeks success, money, and power is to "kiss the leper," to spend time with those who are outcasts in our culture. The poor, the dying, the sick, the alienated. When we are with those who on the outside of our culture peking order, we find a different set of values and moreover, we find God. So much of me wants to be lost in my grand ideas and reflections, away from the noise and urgency of other people, but I cannot escape the fact that growth for all humans involves the messiness of genuine human contact and the struggles of intimacy.