Always fill in the subject line with a topic that means something to your reader not decals or important but deadline for new parking decals
put your main point in the opening sentence most readers won't stick around for a surprise ending
never being a message with a vague this (this needs to be done by 5:00.) always specify what you are writing about
don't use ALL CAPITALS or all lower case letters either
as a general rule please avoid text speak (abbreviations and acronyms
be brief and polite if your message runs loner than two or the short paragraphs consider (a) reducing the message or (b) providing an attachment
remember to say please and thank you and mean it
add a signature block with appropriate contact information (in most cases your name business address and phone number along with a legal disclaimer if required by your company )
edit and proofread before hitting send
finally reply promptly to serious messages if you need more than 24 hours to collect information or make a decision send a brief response explaining the delay.