11 rules for writing the perfect email subject line for job hunting

A typical inbox reveals about 60 characters of an email's subject line, while a mobile phone shows just 25 to 30 characters, Augustine says.

With such limited space, eliminate any unnecessary words like "hello," and get right to the point in about six to eight words.

Most emails are now read on mobile phones, says Dmitri Leonov, a VP at email management service SaneBox.

Since you don't know how much of the subject line hiring managers would be able to see from their smartphones, it's important to put the most important information at the beginning of the subject line. Otherwise, compelling details could get cut off.

Recruiters spend just six seconds reviewing a résumé, says Augustine, so they likely spend even less time scanning a job seeker's email.

The subject line should communicate exactly who you are and what you're looking for without a recruiter needing to open the email.

Don't use a vague subject line like "resume for opening," and instead specify your name and which opening you're applying for. You should also include the job's ID if it has one.

If you're thanking someone for an interview or conversation you had, include when and where this happened, suggests Danny Rubin in his book, "Wait, How Do I Write This Email?"

Instead of a simple, "Thank you," try something like, "Thanks for today's coffee meeting at Starbucks."

"Don't make people scan their brains to remember you; put all the relevant info in one line," Rubin writes.

Hiring managers typically have filters and folders set up to manage their email and probably won't focus on your message when they first see it, says Leonov. That's why it's important to include keywords like "job application" or "job candidate" that will make the email searchable later.

The subject line should be a place to distinguish yourself and immediately catch a recruiter's eye. If it would be easily understood by the recruiter, Augustine recommends including any acronyms you have that are pertinent to the job. For example, you might add MBA, CPA, or Ph.D. after your name, depending on its relevancy to the position.

If you've been referred by a mutual acquaintance, do not save that for the body of the email, says Augustine. Put it in the subject line to grab the hiring manager's attention right away.

Moreover, she suggests beginning the subject line with the person's full name. For example, Friend of Jane Doe, interested in analyst position.

In a LinkedIn article, Adam Grant, a Wharton professor and organizational psychologist, points to research that shows people are more likely to read emails with subject lines that create curiosity or provide utility.

If you're feeling brave, you might try a subject line like, "9 reasons you should move forward with Jane as your new sales manager." It creates curiosity while also including the important details.

If you begin a thought or question that ends in the email, then the reader is once again forced to open the email, which is annoying, Augustine previously told Business Insider. The goal is to be clear and respectful of the recipient's time.

Using all caps may get someone's attention, but in the wrong way. It's the digital equivalent of yelling, and your job is to make the email as easy as possible for a recruiter to read rather than giving them anxiety, says Leonov. Instead, use dashes or colons to separate thoughts, and avoid caps and special characters like exclamation points.

This is an update of a story originally written by Jenna Goudreau.