“The use of ‘Black Friday’ and ‘Cyber Monday’ in the subject lines nearly doubled year-on-year, but that doesn’t mean engagement rates followed. ‘Black Friday’ saw a 14% higher open rate than in 2014 and a 43% increase compared to the general 2015 Black Friday weekend open rate.”
Don’t forget about your subject lines! Be sure to test them regularly to see what keywords garner the most results, and to optimize as necessary. Your subject line is your opening line, so it needs to be attention-worthy and keyword-friendly.