Read Bustedhalo.com daily! =)
Read about the great ones: Gandhi, Dorothy Day, Martin Luther King Jr. Read good contemporary spiritual writers: John Dear, S.J., Annie Lamott, Anthony DeMello, S.J., Richard Rohr, Megan McKenna. There are many more.
Read and re-read the gospels and try and attend Mass often. Usually, busyness can make it seem we have no time for prayer and reflection, but there are always 10 minute spaces where one can pull out the rosary beads.
One practice many young people doing a year of service find helpful is spiritual direction. Ask a local priest (Jesuits especially) about it. Sisters, Campus Ministers and other qualified lay people would be good sources too. She or he most likely will know women and men who are spiritual directors in your area. Spiritual Directors International also has a good listing of people. A good director is like a coach who guides you and helps you notice and name God’s presence and action in your life.
Lastly, read good novels and see good movies. Go to a local high school play. When you are in new places with new work serving the poor, you need your spirit nourished by good art and fun evenings. No one needs a miserable servant. The happier you are, the more God’s grace can shine through you for those you serve.