I learned this trick from Alex Berman whose book “Cold Email Manifesto” I recommend.
How do you get potential customers to open the email?
You need a good subject line.
Luckily this is the easy part.
Out of all the subjects lines tested over thousands of emails, this subject line has outperformed other subjects in testing
Subject: Quick question!
Test it in your campaigns and you’ll be sure to get a high number of opens.