It has to catch the eye of the reader
While headlines may be just one line of text, it has to be properly formatted for the eyes to catch the news. Eye-catching could mean anything, but it has to serve a purpose.
Choose headline font that are designed for their purpose. For headlines, the most common types include Caslon, Mercury Display and Kis. Headlines must be properly spaced and must be legible. Some level of contrast will also help in creating emphasis. Some fonts are thick enough to be used as is but depending on your choice of font, you could also use the bold format to create more emphasis.
A certain conviction should be present with the font choice
When you make the choice earlier on for a publication or maybe certain themes, it will help create a consistent image for the magazine or any other project you are doing. For blogs, this could be the selection of fonts for the title page. Making choices will allow you to experiment on different styles. Always make sure that the font will work well with the body copy and if you have a separate font for the name of your project, the headline must be able to stand out, but still look natural with other fonts. Some publications are known to change fonts every now and then and it has become an acceptable method, but at the end of the day, it would be good to have a go-to font for much of your content.