Know the Subject Length
Email software displays only so many characters in a subject line. Microsoft Outlook displays 66 characters, including spaces. Web-based services like Gmail depend on the width of the browser window. Smartphone email might show only a couple of dozen. Ensure the most compelling part of your message is visible to get your emails opened.
Moderate Your Send-Out Rate
Nothing exceeds like excess, and the boundary between BFF and stalker is slim. Be moderate in your email outreach, so that recipients don’t categorize you as a junk mail sender.
From 10 WAYS TO MAKE PEOPLE ACTUALLY READ YOUR EMAILS (By Erik Sherman, business and tech writer for Inc, The New York Times Magazine, Fortune, and more.)