10 Rules to Reverse the Email Spiral
Emailcharter is a page with ten short and practical rules to better email writing. As stated in the first rule, the underlying principle is to respect recipient's time:
The onus is on you to minimize the time your email will take to process.
I discovered EmailCharter while listening to Tim Ferris' conversation with Maria Popova. (Maria Popova is the sole author of Brain Pickings, a page that gets more than 5 million readers per month.)