Software architecture design principles

GRASP - General Responsibility Assignment Software Patterns (or Principles) consists of guidelines for assigning responsibility to classes and objects in object-oriented design. The different patterns and principles used in GRASP are: Controller, Creator, Indirection, Information Expert, High Cohesion, Low Coupling, Polymorphism, Protected Variations, and Pure Fabrication.
SOLID (ru)
KISS Keep it simple, stupid
DRY Don't repeat yourself
YAGNI You aren't gonna need it
Worse is better
Law of Demeter, LoD Each unit should have only limited knowledge about other units: only units "closely" related to the current unit. Each unit should only talk to its friends; don't talk to strangers. Only talk to your immediate friends.