What are the best practices for email subject lines?

What are the best practices for email subject lines?

Hi Friend,
best practices for effective email subject lines

• Get personal.
• Segment your audience for a highly relevant message.
• Be concise and clear about what your email delivers.
• Don't over-promise or mislead.
• A/B test different email subject lines.
• Avoid spam trigger words.
• Use numbers.
• Avoid emojis.