How to write good technical documentation

Yesterday I was writing a relatively complex and lengthy technical document for a client. I was struggling. It was a kind of document that will be published and read by many people of various backgrounds. Not being able to make assumptions, I had to really watch my use of terms, logic of presentation etc. It is not easy, at least it is not easy for me. I do not have formal training in technical writing. My experience is vast but one-sided: I mostly have written for fellow developers. This new experience thrills me. I arrived at the decision to grab any opportunity to write documents for diverse audience.

Now I know why good technical writers are expensive and hard to find.

The first law I discovered for myself, and sorry if it is a commonplace, is this. Write for idiots. Idiots will like it, it make them feel adequate. Smart people will like it making them feel superiour.

Writing for idiots, as I discovered, is hard. It has to be easy to understand but not lengthy.
So I am thankful to all idiots out there. Myself included. Looking backwards, I always preferred documents and books written for idiots. So thanks to all the idiots again (idiots like repitition of important points) and authors making effort writing for them. Myself included.