In business communication: a) start with the end, b) use proper etiquette and c) be concise. Your question makes it appear that you need help with all of these.
A) Start with the End:
Start your message with the most important information/bullet points/summary first. Don't make the reader wait, even for bad news, because you might not have a reader for long. By contrast in other forms of writing (novel, story, comedy routine, etc.) encourage you to build the story and lead to a punchline. In business this approach backfires. Start with the important information and let reader decide whether to continue reading. This also saves the reader from sifting through "story" to get to the point.
B) Use Proper Etiquette:
When in doubt, be respectful by being formal. For example: avoid first names and use "Mr. X, Ms. X". Also avoid sounding conversational. The point here is that by being "formal" you will never offend. They might request less informality (i.e. "Please call me Chris") but calling them "Chris" before being asked may be too much.
Also, written language should be more formal than verbal. Even if you use an informal greeting, keep nearly everything else formal. Avoid conversational tones/wording, avoid contractions and avoid saying anything "friendly" in favor of formal or dry language. With spoken language this may sound too formal, but with written language it reads well and appears respectful.
C) Be Concise:
You probably use more words than necessary, maybe to "clarify" information but with the opposite effect. Most people use writing techniques taught by educators, aspiring authors and actual authors - people that favor intrigue and entertainment over concise communication. You have a different audience so avoid those techniques and advice.
After writing a draft message, review it and try to reduce the number of words by 50%. Even after that try to take out more words. In business, fewer words are more likely to be read. If you use MS Word or a similar program, aim for readability at a 6th grade level or lower (like a newspaper). Using complex or unusual words reduces communication.
A couple good reference books:
Write to the Point http://www.amazon.com/gp/product/B0085A7E7Y/ref=dp-kindle-redirect?ie=UTF8&btkr=1
How To Say It http://www.amazon.com/How-Say-Third-Sentences-Paragraphs-ebook/dp/B001TSZ67O/ref=sr_1_1?s=digital-text&ie=UTF8&qid=1450517749&sr=1-1&keywords=How+to+say+it
The Pyramid Principle http://www.amazon.com/Pyramid-Principle-Logic-Writing-Thinking/dp/0273710516/ref=sr_1_1?ie=UTF8&qid=1450517785&sr=8-1&keywords=pyramid+principle