How to win friends and influence people—online

The less time your recipient has to spend figuring out what you need, the more likely they’ll be to respond—and pay attention to your messages in the future.

and

Instead of demanding changes and hitting send, take the time to explain not only how, but why you think something could be improved.

From a post on the Dropbox Blog (and if you’re requesting changes to design work, don’t worry about the “how” and just start with the “why”). To be good at email requires both short game and long game. And it’s easy to lose sight of the latter when you’re trying to get that one little thing done and off of your plate. But every time you hit “send” on a bad email, you’re losing trust and respect as a communicator.