Summarize this article:

If you're writing a headline for an ad, your headline will also have to serve to promote a product to a reader. Learn what the product being advertised does, what benefits it can bring to readers, and use this information to write an alluring headline. For example, if the product being advertised is used to treat chronic back pain, your headline should be written to target those who suffer from back pain and mention this potential benefit (e.g., Get immediate relief for chronic back pain with one simple product!). Understanding your target audience is the first step towards writing an effective headline. If you attempt to reach everyone, you'll come across as vague and impress no one. Keep your intended audience in mind and try to target them specifically in your headline.  Having your target audience in mind will ensure that your headlines are always written with purpose and direction. For example, if you're writing a headline for a magazine whose readership falls into a specific demographic, cater your headline to that demographic (e.g., 17 ways to study abroad for free during your sophomore year of college). Unless the subject of your writing is incredibly niche, it's likely that yours will not be the first headline on the topic. If others have written headlines around the same subject as yours, research how they wrote them and make sure yours is unique. This is very important for making sure that your headline attracts readers. If it doesn't stand out from the thousands of other headlines readers see every day, your chances of having readers actually read your article will go down. You want to promise your reader something of value in exchange for reading past the headline. Emphasize the end result in and around your headline to seduce the reader into reading your article. For example, if you're promoting a cookbook, don't emphasize the raw ingredients or the amount of time it takes to cook a meal. Instead, show a presentable meal served on a set dinner table to “promise” the reader that that's what they can have in exchange for reading past your headline.

Summary:
Research the product if you're writing an advertisement headline. Identify the target audience for your headline. Learn what others have written on the subject of your headline. Consider what your article will offer the reader.