CLEAR= Leave no doubt in your reader's mind. Help yourself by being specific, avoiding vague expressions, using familiar words and using simple English. Remember also to use straightforward language that your reader can understand, written in a friendly, natural, conversational style.
LOGICAL= Structure your messages logically, remembering to use the 4 point plan. Start with an introduction, develop your points logically in the central section, and come to a natural conclusion in which you state the action you need from the reader. Finish with an appropriate one-liner.
EMPATHETIC= Put yourself in your reader's place and ask yourself how the reader will feel when he/she reads your message. If anything is unclear, or if anything is worded badly, then change it before you send it.
ACCURATE= Make sure all the relevant details are included - times, dates, names, facts and figures.
RIGHT= Proofread carefully(not just spell check!) to make sure everything is 100% right before you send the message.
Source: Model Business letters, E-mails & other business documents (sixth edition)
Shirley taylor, FT prentice hall, Pearson education pg: 42, Unit 1,
written communication-An overview.