The difference between good and great headlines can be that a good headline will reach 1,000 people, while a great headline can reach 1,000,000 people.
In order to create a great headline, you must find the language/customer fit.
What resonates the best with your customers?
Do an A/B test on headlines using an online service that offers it.
You can use something like Mailchimp, Google Adwords, or Facebook ads.
Don’t trust intuition.
Even experienced marketers cannot tell you what works better than the data from A/B tests.