"How to Email a Professor"
Use paragraph breaks to help organize your message
Reading a big block of words is unappealing. Try to break thoughts up appropriately.
Write the body of the email message first; fill in the address in the TO: line last
This is a good technique so the message won't be sent before it has been proof read for typos and incomplete thoughts.
Start with a new message
Professors may mistake this as an attempt to talk more about that previous topic. Avoid replying simply to older messages unless it's relevant.
Don't use e-mail to rant or whine
Rants and whining episodes aren't very fun to read and often lead to an undesirable response. If you must rant, then write the message out, but don't press send.
Do not address a professor by their first name unless they have explicitly instructed you to do so
If your professor has instructed you to address them a certain way, then you can use that. If not, stick with the "Dear Professor Last Name" formula.
Write an informative subject heading
If your professor hasn't told you a specific heading to use for emails, than try to make the heading as specific as possible, such as by using the course number.
Use your professor's last name in your salutation
Professors prefer "Dear Professor Lee" to just "Dear Professor" or "Dear Prof". Professors often grow to dislike students that don't address them as they see fit.
Use your university email account
Professors receive a lot of emails and have many spam detectors that could place your message from an unrecognized account into a spam folder.
Write grammatically, spell correctly, and use appropriate capitalization
Proper grammar demonstrates to your professor that you care and is a positive presentation of yourself.