A Great Headline Tool
I use CoSchedule (http://coschedule.com/headline-analyzer). You can sign up for a free account and get the use of their amazing headline analyzer for free. Of course there are perks to a paid subscription, but that's not what I am here to tell you about.
The goal to the headline analyzer is to get a green score and an A+ rating.
I aim for an A+ and a score of 75 or above
It looks at what words you use, the balance of those words, the order in which you use them, the unmber of characters and word count and type of headline you have created. Basically it looks at the overall structure, grammar, and readability of your headline.
Start by typing in your keyword string or the proposed headline you think will work, then hit enter. This goes a long way to show how much more powerful a headline can become.