Take your audience into consideration when building your documentation
Users Colleagues Partners
What is their technical ability?
Are they "an input" into the process?
Are they the "main actor" in the process?
Are they "an output" of the process?
Tone
"When we're helping people with technical problems, impatience is perceived as arrogance. "My time is more important than your problem." Hubris is perceived as belittling. And laziness? Well, that's just laziness.
Being patient and kind, helping people move at their own pace (even when it feels slow), is perceived as respect. Welcoming people at whatever level they are, and patiently helping them move up to the next level, is how you build your community.
Don't make people feel stupid: This must be a core goal.
Even if everyone else in the world is a jerk, you don't have to be."
-- Source: http://opensource.com/business/15/5/write-better-docs