The concept of a single best day and time to send an email is misleading. Instead, marketers should vary send times throughout the week to reach different segments of their audience. The key metric is the aggregate number of unique individuals engaged weekly, not the performance of a single blast.

Using subject lines like "Verify your active status" can lift open rates by 27-31% for contacts who haven't engaged in over a year. While effective for reactivation, this slightly gimmicky approach will also annoy some users, leading to a higher-than-usual unsubscribe rate and negative replies, which requires 'thick skin'.

For B2B re-engagement, a highly effective subject line is "Are you still with [Company Name]?". This personalizes the email at scale by dynamically inserting the contact's employer. It grabs attention and prompts an open to confirm or update their status, successfully re-engaging them with your content or offers.

From Nov 20th to Dec 20th, sending a personal letter-style email from a founder or executive to unengaged contacts can increase open rates by 40%. The key is changing the "from name" to a person, not the brand, and using a subject line that acknowledges their absence. This strategy works for both B2B and B2C brands.

Combine two specific audience identifiers in your subject line, like role and company attribute ("Mid-market CMOs") or interest and a pain point ("Beauty fans with sensitive skin"). This "double personalization" tactic reportedly increases B2B open rates by 24% and B2C by 29% by making the message feel hyper-relevant.

Getting users to reply to your marketing emails is the number one signal to email providers that your content is valued. This action helps your future emails avoid the spam or junk folder, significantly improving deliverability and overall engagement.

Prompting subscribers with simple, non-work-related questions (e.g., "What's your favorite holiday cookie?") encourages replies. This builds a conversational relationship, improves engagement signals, and positively impacts email deliverability and open rates.

Your email signature is valuable, underutilized real estate. Adding a simple holiday-focused message, a thank you, and a link to 'best of the year' content can increase CTRs by over 40% in December as you're reaching highly relevant business contacts.

Animated GIFs in emails see their highest performance during the November-December period. This seasonal lift is attributed to audiences being in a more receptive and festive mood, making it a prime time to test this tactic for increased engagement and to stand out in crowded inboxes.