Eric (Steven) Raymond stated these basic rules in his 2003 publication, The Art of Unix Programming:

  • Rule of Modularity: Write simple parts connected by clean interfaces.
  • Rule of Clarity: Clarity is better than cleverness.
  • Rule of Composition: Design programs to be connected with other programs.
  • Rule of Separation: Separate policy from mechanism; separate interfaces from engines.
  • Rule of Simplicity: Design for simplicity; add complexity only where you must.
  • Rule of Parsimony: Write a big program only when it is clear by demonstration that nothing else will do.
  • Rule of Transparency: Design for visibility to make inspection and debugging easier.
  • Rule of Robustness: Robustness is the child of transparency and simplicity.
  • Rule of Representation: Fold knowledge into data, so program logic can be stupid and robust.
  • Rule of Least Surprise: In interface design, always do the least surprising thing.
  • Rule of Silence: When a program has nothing surprising to say, it should say nothing.
  • Rule of Repair: Repair what you can — but when you must fail, fail noisily and as soon as possible.
  • Rule of Economy: Programmer time is expensive; conserve it in preference to machine time.
  • Rule of Generation: Avoid hand-hacking; write programs to write programs when you can.
  • Rule of Optimization: Prototype before polishing. Get it working before you optimize it.
  • Rule of Diversity: Distrust all claims for one true way.
  • Rule of Extensibility: Design for the future, because it will be here sooner than you think.

Most - if not all - applies snuggly to web development too (and why would it not; it's programming and more often than not, directed towards servers 'running' on *nix OS'es, be it Linux, Unix, well OSX too).