Anyone who's ever applied for a job knows how stressful it can be. And for some, the hardest part is the cover letter.

It should be professional, but make you stand out. It should be short, but not too short.

While a cover letter can seem like a formality, it's an important first step in the process.

"It's your personal sales brochure," said James Innes, chairman of the James Innes Group and author of several career books. No wonder it's so daunting.

Here are a few tips to help you pen the cover letter most likely to get you hired.

Read the job posting closely

"The things that come at the top of the job description are the most important," said Martin Yate, career coach and bestselling author of the Knock 'Em Dead series.

To make sure you highlight the traits your potential employer really cares about, refer to the skills listed in the job posting to inform how you talk about yourself in your letter.

Yate suggested going a step further by reviewing job listings at several companies, and seeing if any skills or traits are repeated across an industry. "I would recommend collecting half a dozen job postings," he said. "Look at what they have in common."

Quality over quantity

When you're first looking for jobs, it can be tempting to send out a generic cover letter to as many employers as possible. But that doesn't work, Innes said. Recruiters can tell, and they don't like it.

Keith Bevans, head of Bain & Company's global consultant recruiting, warned that a poor cover letter can hurt an applicant's chances of getting the job. "The cover letter becomes an important data point on how good they are at certain skills that might be relevant to the job they're applying for," he said.

Related: How to answer the salary question during a job interview

Make a good first impression by ditching "to whom it may concern." Instead, look for the name of a hiring manager and address it to them. You should also try to find out a little bit about them, and say something nice about their achievements. "If you can flatter someone in the opening line and create a connection, you've got their attention," said Yate.

Tell a good story

Once you've determined what matters to employers, figure out what type of story you want to tell about yourself -- and be succinct.

"The best cover letters tend to be short and to the point," Bevans said. You don't want to repeat what's in your résumé.

Rather than telling employers what you think you're capable of, tell them what you've already achieved. "People are hired on credentials, not potential," said Yate. "We want to leave out things like 'I think I could do a great job.'" Offer specific, relevant examples, Innes added.

Related: What top employers look for in new college grads

Bevans noted that if you're going to use buzzy terms to describe yourself, you should be able to back them up. "A lot of students write cover letters that are like treasure maps with no treasure," he said. "If you say you're a good team player" you should have a specific example to back that up, said Bevans.

Stick to clean templates

Yate recommended using one of two possible cover letter formats. The first is a simple letter, made up of a few paragraphs and lasting no longer than a single page. First get your reader's attention with a personal reference, then name the position you're applying for. In the following paragraphs, lay out your relevant skills and experiences. Conclude by outlining an actionable next step. Rather than telling the reader you look forward to hearing from them, say you'll reach out by a certain date to follow up.

The second format is called an executive briefing. You still write a paragraph at the top explaining what you're applying for, and one at the bottom with a plan of action. But instead of writing out some paragraphs in between, set up two columns: One with a list of requirements pulled form the job posting, and one with a list of your corresponding skills and achievements. This format lets recruiters see clearly why your experience makes you a good fit for the job.

Check your work

"Presentation is important," said Innes. That means not only that your cover letter should be cleanly laid out, but also that your spelling and grammar have to be perfect.

"Recruiters sit and read through a lot of résumés," Innes said. "You become very good at spotting those errors." Chances are, he said, recruiters will just trash a cover letter with spelling or grammatical errors.