Some useful resources

• Getting Started with Topic-Based Writing
  A good introduction to Topic-based writing from  TechWhirl
• Documenting APIs
  A guide for technical writers and engineers
• Smashing Magazine
  50 Free Resources That Will Improve Your Writing Skills
• Core Practices for Agile/Lean Documentation
  This article summarizes common  best practices for increasing the agility of documentation
• The Elements of Style
  The classic reference from William Strunk, Jr
• Online Writing Lab (OWL)
  Free writing resources and instructional materials.
• Technical Writing Is Loving Language
  Useful references to tame technical writing in the real world
• Google courses
  Overview of technical writing courses
• Content Engineering
  What Is Content Engineering?