Reddit reviews Technical Writing and Professional Communication

Exactly. I have two books I recommend for people who want to write software documentation.

• Writing Software Documentation by Thomas T. Barker. This was the text book of my favorite class at ASU when I was in college. It's well-written, amusing, and has lots of great examples. You can find older editions super-cheap, and even if you're using the old edition, you'll still learn TONS about why technical writers write the way they do.
  
• Technical Writing and Professional Communication by Olsen and Hucken. Another from my days at college, and ASU has a fantastic Technical Communication program. This one is also pretty darned great.
  
  Outside of my base recommendations, I recommend Business and Administrative Communication by Kitty O. Locker. Technical writers are often called upon to do other tasks within a business--things like feasibility studies, RFPs, and things of that nature. This book cost me $120 in 2004 when I was studying at ASU... it's one of three I did not sell back because it was so useful to me (the other two are in the first list!).
  
  APIs are a huge deal in software development these days. There are so many different ways of documenting them. Make sure you understand the concept and study different documentation methods for APIS... if an interviewer asks you if you know how to document, or have experience documenting APIs, you will not get the job if you say no.
  
  If you haven't used the software don't say you have, it will show immediately, and you won't have a job. RoboHelp and Flare are huge hulking behemoths. Also have some experience with photoshop (or Gimp) and illustrator (or Inkscape). It may not be a requirement, but it's invaluable to at least know how to scale images, change colors of images, create vector drawings for basic shapes and maybe even icons.
  
  Have some experience using Acrobat Pro. Have some experience with HTML and CSS. Markdown is also good to know. Experience administering wikis helps, too. And SharePoint experience can only help.
  
  Technical writing is so much more than having technical experience. :)
  
  edit: formatting