Keep email subject lines short!
Last year, 61% of all emails were opened on mobile devices, which means that how you manage that small bit of real estate on your prospects mobile device is critical to getting your message across effectively. How many words should you use? Around 7. Or approximately 40 characters.
Don't use deception!
Let's be honest for a second, sales professionals aren't viewed in a particularly positive light primarily due to the actions of a few bad apples. Here at the Maestro Group, we teach that "sales is not dirty," because, if you are a professional, it isn't. So what does deception in a cold email subject line look like? "Re:" Yes, they may open your email, but at what cost? Once they figure out that you duped them, you will have tarnished your reputation with them forever.
Use appropriate language!
Since you did some solid research on your prospect (you did research your prospect before even thinking about emailing them, right?) you have a bunch of information about them, and some of that information should revolve around the kind of language and tone they use, allowing you to craft your subject line and the following message to them and the way they speak. Emailing into the C-suite? Being too informal will get your email tossed, but being too formal doesn't make your email stand out from the crowd. It definitely is a delicate balance and it take time to master.