I think this should apply for any kind of email, not just for busy people. Actually, this applies to most kinds of writing too.

It'll come off much better if it's well-worded but simple and to-the-point. The more fluffy sentences you add to your email, blog post, internet comment or product copy, the less professional it starts to sound.

True, but long copy sales letters have been shown to be effective. It all depends on the audience.

long copy sales letters tend to be aimed at the bottom 1 percent.

Balance the two.

Be direct in your requests, include enough details (pick the right ones!), say thank you, and cut out everything else.

To quote the Bard: Brevity is the soul of wit.

Therefore, be brief when you can, but always..be polite.

I wish I could upvote this more than once. I'm a professional so I don't need requests to be sugar coated. I also don't need lots of detail in the first email. If I'm interested then I will get back to you!

This comment is all the better for being both a description and instance of the advice.

"Write tight."