The best way to prevent your rights being exploited at work is to join a union. The second best way is to know your workplace rights and to be able to identify when someone is trying to rip you off! The Young Workers Centre is there to help you out. Visit the Young Workers Centre here.
If you or someone you know if getting a the raw deal at work then get in contact with the Young Workers Centre for information or to organise a consultation on your specific situation.