Cracking a 64-Bit Encryption

I am new to this site and hacking in general so I apologize if I do not post with the proper etiquette.

I am curious what the fastest, or most efficient, way to crack a 64-bit encryption. Obviously brute force could take a good while and let us say I do not know much more than it is 64-bit.

Does anyone have a better way to start or go about this?

Thanks!