Adopt a simple style, and convey the message clearly. For instance, if the email informs of a change in transportation arrangements, state the reason upfront and provide details in the following paragraphs. Do not leave it for the reader to guess the main point or theme from a descriptive paragraph that starts with the background of the issue and then moves to proposed changes, without clarity on whether the “proposed" changes are actually final.
Provide details, without leaving anything to assumptions to avoid common communication problems. For instance an email that reads, “Hope you received the proposal. Please call me when you are free, to discuss" leaves the reader confused as to which of the many proposals he has received is the one referred to by the sender. Rephrasing it as “Hope you have reviewed the proposal I sent last Monday regarding enhancing network security. Please call me when you are free, to discuss on the matter" lends clarity.
Make proposals enticing enough for the recipient by focusing on what the recipient needs to do and the gains resulting from such action. If the email becomes long and complicated, leave the details to a next email to follow, after the recipient expresses interest.
Make only point per email, so that the recipient may reply promptly and directly. For instance, mentioning about the need to hold a discussion and in the same email referring to an unrelated report may delay a response, as the recipient needs answers for both cases in order to reply. It may also stifle a reply, or make a reply cumbersome, if the need to correct the report requires sending a copy to other staff, when the discussion may be confidential from such staff.