Practical Trade Secret Tips?

Other than the score of legal agreements (NDAs, work for hire, security policies, background checks) and physical/data security (restricted access, encryption, etc.), what are some practical ways to deal with running a startup while maintaining trade secrets?

For instance, I can make sure that only developers who absolutely need access to certain data for their work have such access, but are more "clever" methods often employed, such as somehow splitting up crucial algorithms (if possible) and data so that only partial information is available to any individual or group? Something akin to the security that highly anticipated movie productions use to protect scripts or stories before they are released as movies by splitting the scripts into sections and restricting access?

How does a company like Google deal with access to its page-rank algorithm? Do certain high-level developers and managers get access to the algorithm completely, or is it more convoluted than that? Or are the legal agreements enough to maintain the necessary secrecy?

I'm at the beginning of a startup that will depend on trade secrets for some algorithmic stuff and I'm curious what other companies have implemented practically to deal with this.