While working on internal Hyper-V documentation I wrote over 200 pages of content (mostly technical). I got some reviews by Rob Dendtler (thx Rob!), and the most interesting things I learned from him were not technical, but tips regarding writing style. The two common mistakes I made (and they are common in general as I learned):
Remembering those two rules, can make your documents more objective and clear. At least that helped me a lot.