Many marketers mistakenly summarize their entire email in the subject line, removing any incentive to open it. To increase curiosity, provide only a hint or a compelling data point from the email's content. This creates an information gap that subscribers feel compelled to close by clicking.

To maximize open rates, craft short (1-4 word) subject lines that mimic internal emails. This means using all lowercase or sentence case capitalization. Critically, avoid elements that scream "sales email," such as questions, numbers (e.g., "10x"), and even customer name-dropping, which hurts opens despite being effective in the email body.

Begin email subject lines with conjunctions to create an immediate sense of an ongoing story or a problem to be solved (e.g., "And then this happened" or "But here's the problem"). This copywriting technique sparks curiosity across any industry, prompting recipients to open the email to get the full context, lifting open rates by around 17%.

To combat users' rapid 'social scroll' behavior within their email inbox, use subject lines that disrupt their scanning pattern. Phrases like "wait... this worked?" or "okay... this surprised me" create a crucial millisecond pause, which can radically increase email open rates.

A highly effective email tactic is using a compelling statistic as the entire subject line, with no other text or call to action. This piques curiosity by presenting a data-driven statement, leading to an average open rate increase of 19%.

A counterintuitive tactic suggests beginning email subject lines with conjunctions like 'and,' 'but,' or 'plus'. This grammatically incorrect but novel approach disrupts reader expectations, sparking curiosity and leading to a claimed 15% lift in open rates, especially when the starting word is capitalized.

Switching from clear but safe subject lines (e.g., '3 ways to...') to provocative, curiosity-piquing ones dramatically improved open rates. The speaker notes that if a subject line feels slightly uncomfortable to send, it's probably a good sign.

A counterintuitive yet effective email tactic is capitalizing an entire word in the middle of a subject line, not at the start or end. This simple, cost-free A/B test is trending because it breaks visual patterns in the inbox, leading to a reported 16% open rate increase for B2B and 21% for B2C.

Many marketers mistakenly reveal the entire value of an email in the subject line, killing any reason to open it. To maximize opens, provide a compelling hint or create a curiosity gap rather than giving away the full story.