Getting messages read.
WHAT AFFECTS THEM
Whether the message arrives in the inbox at all The sender name, and whether it is recognised The subject line Timing Whether previous messages were useful
THE LARGEST FACTOR
Deliverability. A message in spam is not opened regardless of the subject line.
Fix authentication before optimising anything else.
THE SENDER NAME
Consistent, and recognisably your business. Recognition is what produces opens.
SUBJECT LINES
Specific beats clever. Say what the message contains.
Short enough to display fully on a phone.
Test alternatives if your platform supports it and your list is large enough for the result to mean anything.
PREVIEW TEXT
The line shown alongside the subject. Write it deliberately.
Most senders leave it defaulting to their header, which wastes it.
TIMING
Matters less than people claim. Test rather than following general advice.
THE UNDERLYING FACTOR
Whether people found the last message worth reading.
Consistently useful content is what produces opens over time.