I have a new rule:  one point or one question per email.  Sorry, but more than one point, subject, question, etc. just seems to confuse people.  If I ask someone three questions they may only answer two.  If I made a point in that email that they disagree with, they may not answer any of my questions, but discuss why they disagree instead.

It’s really my fault anyway.  I know you’re busy; that you may not get my email until you decide to respond to everyone in bulk.

Just don’t blame me if I send you thirteen separate emails with thirteen separate questions.