Thomas Green originally defined 14 cognitive dimensions:

  • Abstraction gradient,
  • Closeness of mapping,
  • Consistency,
  • Diffuseness / terseness,
  • Error-proneness,
  • Hard mental operations,
  • Hidden dependencies,
  • Juxtaposability,
  • Premature commitment,
  • Progressive evaluation,
  • Role-expressiveness,
  • Secondary notation and excape from formalism,
  • Viscosity, and
  • Visibility.

-- Cognitive dimensions of notations

I strongly believe that you can “begin anywhere” and don’t need to learn technologies in any particular order. But I also place great value in gaining expertise. Personally I’ve mostly been interested in creating user interfaces.

-- More on the topic from Dan Abramov, The Elements of UI Engineering.

Jakob Nielsen: UI Checklist.