Letters of Note has a great letter from Kurt Vonnegut to some NY high school students:

What I had to say to you, moreover, would not take long, to wit: Practice any art, music, singing, dancing, acting, drawing, painting, sculpting, poetry, fiction, essays, reportage, no matter how well or badly, not to get money and fame, but to experience becoming, to find out what's inside you, to make your soul grow.