My creative writing teacher, Dr. Rand, gave us what she called 'Writer's Slogans.' Perhaps her own favorite slogan was "Work from abundance." She had us keep a journal in which we could write down anything from our observations about the campus, to a list of all the shades of blue we could think of, to quotations we liked, to comments about books and poems we read. Her thinking was, it's easier to find inspiration if you have plenty to work with.
She also encouraged us to read excellent writing to learn the difference between excellent work and "not quite there yet" work. This exercise wasn't meant for us to compare ourselves to others, just to give us an idea how to find our own voices.