before you crack search more for the password it could be just front of you,
Brute-force or
Dictionary attack, don't know any other ways to crack them, don't think there is other ways, the two take time it depend with the password and the method, try
Dictionary attack if there is no result you don't have other choice then
Brute-force and you will have to wait a long long time _^
Definition:
Brute-forceDictionary attack