Design Principles, Best Practices and Design Patterns for C (or Procedural Programming in general)?

Are there any known design principles, best-practices and design patterns that one can follow while designing a C project? Or useful design principles for procedural (imperative) programming in general?

(I'm child of the 'object-oriented generation' and have to design a large C project for the first time)

Information hiding - as espoused by Parnas (Software Fundamentals).

Careful management of headers and visibility:

• Everything in a source file that can be hidden from the outside world should be; only the documented external interface should be exposed.
• Everything that is exposed is declared in a header.
• That header is used where the functionality is needed (and where it is defined).
• The header is self-contained - when you need it, you use it, and you don't have to fret about 'what other headers do I also have to include' because the header ensures it works by including anything it needs to make it work.

• The header is self-protected - so it does not matter if it is included multiple times.

  #ifndef HEADER_H_INCLUDED
  #define HEADER_H_INCLUDED
  ...rest of header contents, including other #include lines if necessary
  #endif /* HEADER_H_INCLUDED */
  

• Design sets of functions to work on 'objects' (usually structures) - and use those functions rather than poking around the innards of the structure in the code that is using it. Think of it as self-imposed encapsulation.