Ask HN: How to get started as a Technical Writer

I've been told that I am very articulate and explain technical things in a very easy to understand manner. I've also made several HOW TO Guides, Quick Start Guides both in blog format, as well as in Video / Screencast format.

So I was thinking of trying my hand at Technical Writing.

Can some of you Industry veterans give me some tips and pointer, DOs / DON'T relating to this? Some specific things I would like to know are...

1) Are there popular GitHub Open Source Projects that are sparse in Documentation? If yes, how do I filter / locate them and start contributing Technical documentation

2) What do you (as a hacker) expect to see, in terms of Documentation, whenever you come across a cool / useful Open Source Project, or a Commercial API / Software Product? What would be most useful to you when you come across a software or API or product that you want to use in your Projects?

3) Do Companies hire Technical Writers fulltime, or is it more like a fixed hourly contract type situation?

4) How is the market? Are there too many, or too little Technical Writers?

5) Is what I am looking to do called by any other name? The Title of the Professional i.e.

6) Anything else you might have insight on / inputs in?

Thanks so much! ~Sean