Don't worry about understanding everything that is said. Practice your listening skills concentrating on the rhythm and sounds of the language. Rent foreign films from the video store. If possible, watch the films with other students. Remember that errors are part of language learning.
Errors are a natural part of language learning.
Even educated native speakers make errors occasionally, so don't expect yourself to be perfect. Don't be afraid to take a few risks in order to learn 10. Develop your own standards and rewards for success. While grades are important, what you learn is more important. Set reasonable learning goals for yourself, and reward yourself for small successes along the way.