Very good article by Marty Zwilling at http://blog.startupprofessionals.com
Here are the top tips he mentions in his article:
Don’t use long complicated sentences.
Short sentences are the best, because they read faster, and reader comprehension is higher in all audiences.
Avoid buzzwords, jargon and acronyms
You may know that NIH means “not invented here” and KISS stands for “keep it simple, stupid,” but don’t assume anybody else does.
Use simple, straightforward language
… like “use” instead of “utilize” and “then” instead of “at that point in time.”
Bullet points are good for organizing and prioritizing multiple elements of a concept or plan.
They help readers see the highlights and key points.
Avoid cryptic bullet points
Flesh them out with brief explanations where explanations are needed. Unexplained bullet points can be mysterious, and usually result in questions.
Don’t overwhelm the plan with too many graphics and flashy colors
Pictures and diagrams can effectively illustrate a point, but too many come across as clutter.
Keep the plan short
You can cover everything you need to convey in 20 to 30 pages of text. If necessary, create a separate backup document for monthly projections, management resumes and other details.