My team adheres to a common set of communication practices. It's part of the Employee Handbook that all new hires into my department are required to read and sign. A summary:
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Email Sender:
- If you need an answer urgently ("urgent" defined as one of two things: it's an emergency, or the information you are lacking is a blocker for what you are currently working on), either pick up the phone and call the other party or send them an IM, instead of emailing them.
- Keep your emails concise and to-the-point. No essays.
- Don't mark your emails as "High Importance" or ask for a read receipt. We treat all emails as high importance, and you can feel assured that your email will be read within 4 hours max (see below).
Email Recipient:
- Read all incoming emails within 4 hours max and respond after reading if possible. If you don't have the information the sender is asking for, or are otherwise not ready for a full response, send a short one indicating that a) you read their email and b) you will respond within X hours, where X is a number that is equal to or less than 24.
- If the response is complex, summarize it as best as you can, and indicate that you will follow up in person or via phone to discuss the details. Don't write an essay back.
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The purpose behind these set of rules is alignment of expectations for both parties. Ever since we implemented them, the vast portion of our "friction" with regards to team communication has disappeared. For example, it's really, really nice to never have to wonder if someone has read your email, and also really nice to know when you can expect a response (which means you can decide whether you want to wait for a response or work on something else in the meantime).
We also have a set of rules for IM (we use Slack) and phone, but those mostly say "be online and available, or mark yourself as Away or Busy as appropriate and people will respect it".