There are a number of ways to fail at this!
1. Don't have the initital meeting with your mentor about thier expectations for you
2. Don't keep the agreed upon schedule. Take off for tests, papers due, meetings, etc....
3. Don't have frequent communication with your mentor. If something occurs that is hindering your ability to keep to the schedule, just stop going in.
4. If you decide you made a mistake and hate the project, tell everyone involved with it. Make your boredom and/or displeasure obvious.
5. If you don't understand something, either guess and goof or stop going in because it is too hard.
7. I am sure there are more so this list will continue to grow.