- Make it easy to open. Think about what shows up in a desktop notification or Gmail preview.
- Make it easy for them to respond on their phone. Ask for one thing: a call, a yes/no, their advice on something specific, etc.
- Make it short, 200 words or less. The longer you ramble, the more chance you have of shooting yourself in the foot.
- Make it easily scan-able. Line-breaks and bullet points do this well, a block of text doesn’t.
- Make it interesting-ish to read. Don’t start every line with “I”.
Bonus: Make them answer. Follow-up! In my experience with these tips, it’s harder not to reply.