Practice German right here on campus or online: vocabulary, grammar, pronunciation, crosswords, audio/video…
Great apps to learn German are listed here. Try duolingo for example!
Quia and the Goethe-Institut have a great choice of exercises of all kinds. Some are very entertaining, check them out! Other excellent sources are busuu or the site compiled by Nancy Thuleen.
Write your own flashcards or use Anki.
Here are your Textbook Sites: Germ 100/110/200, Germ 210/300/310/400/410