You keep doing your work, because you have to, because it's your calling... one does their work for the people. And the more people you can touch, the more wonderful it is... Patti Smith's Advice to the young [more inside]
Use your library. Make more GIF files. Trust the process. Make art - it's good for your heart. from advice to sink in slowly.
"What Do I Put in My Portfolio?" Irene Gallo, art director for science fiction/fantasy publisher Tor Books (and its mainstream imprint Forge), lays down wisdom on how to impress an art director and maybe get one to hire you for a book cover. Aside from being a practical primer for artists on everything from picturing the human figure to how not to annoy an art director at a party, for everyone else it's a glimpse into why SF book covers look the way they do.