Over the years working for Real Estate Webmasters I've sent and recieved alot of emails. Here are my 8 rules for emailing:( so far )
1) Put a good subject line, that attempts to describe what your
email is about. For instance, don't leave it blank or put "stuff"
as your subject. Use a meaningful subject.
2) Never put the entire email message in the subject line. The subject line is for the subject, not the email body.
3) Always "Reply-All" .... This one is a bit complicated. There are times of course when you don't want to have one person included in the email anymore. However, if say one person sent an email to 4 people and you completed the request. Reply all so all the people that got the email know it's been dealt with. If you do remove someone from the email, ensure to indicate that in the reply. This rule has a few exceptions.
4) If you say your going to attatch something to the email. Make
sure you do it.
5) Read your email before hitting send. Does the email you wrote make sence to you?
6) Oh yeah, and don't use capitals. :)
7) Reply to email people send you, if the email is asking a question or requires your reply.
8) Give a person 2-3 days to reply to an email before following up. I usually will try give it 1 week if it's a non-urgent issue. For urgent issues, you may want to use the phone.
Hope that helps!