Focus on the cover letter
It is not uncommon for me to get 100 applications for one spot, so I'm constantly looking for reasons not to advance a candidate to the interview round. Writing a good cover letter is your best shot at getting noticed. If I hate a cover letter, I won't even look at the resume.
Keep it short
I started putting word limits on cover letters because I couldn't stand, nor did I have the time to read, the epically long letters I'd receive. I'm going to give your letter maybe 30 seconds of my time. If you are interested in a job in journalism, you should be able to tell me about yourself and why I should hire you in less than 200 words. I've never hired someone with a longwinded cover letter. Same goes for resumes. No one with fewer than four years of full time work experience needs more than a page. Your summer lifeguarding job does not need five bullet points.
Avoid awkward phrasing and attempts to be overly formal
Introductions like "With this statement, I declare my interest in the position you have advertised on your website" are clumsy and should be avoided. Start with a strong but simple opener, like "I'm excited to be writing to you to apply for the blogging position at Slate." Conversational is much better than stilted.
You are your best advocate
It's not uncommon for me to get a cover letter that opens with, "I am sure you are getting many qualified applicants for this job, many of whom are more qualified than I." If you don't believe you are the best candidate, why should I? This letter is your chance to sell yourself. Don't plant the seed in my mind that you aren't the best candidate for the job. You don't want to be overly cocky, but I'll take confident over meek any day.
Show me that you read my site
It's common for cover letter writers to say, "I love Slate," but that doesn't stand out to me. Be more specific. Who are your favorite writers? What are some recent articles you enjoyed? Detailed flattery will get you further, because it shows you've done your homework. Ninety percent of the cover letters I read for our news blog, the Slatest, mention nothing specific about that particular blog. Here's what one applicant for a recent position wrote (spoiler: I hired him): "I'm particularly drawn to a dynamic news outlet like the Slatest. I appreciate its blend of politics and current affairs, as well as its ability to consistently sniff out the most compelling news pieces and narratives. I dig its sense of humor, too — I can't resist a news blog that picks up on the latest North Korean, pigeon-eating propaganda pieces."
Explain how selecting you will benefit me
This is where candidates often get it totally backward. I frequently read lines like: "I am applying for this paid internship because I think working at Slate would be highly beneficial for me, and would do a lot to help my future job prospects for a career in media for after I graduate from college." I know how working at Slate would strengthen your resume. But I am looking to you, candidate X, to solve a problem for me. My problem is that I need good interns. Explain to me how choosing you will solve my problem.
Here's how one candidate convinced me that his skills were pertinent to the role I was hiring for: "From my editorial experience as managing editor of 34th Street Magazine here at Penn, to my experience in news and culture blogging at LAist.com last summer, I've picked up the tools I need to perform as a Slatest intern with excellence."
I'm not interested in anything you did before college.
Leave anecdotes like this out: "I am a born storyteller, and I've loved writing ever since I won an award for playwriting in the third grade for my series of puppet fairytales." If you are early in your college career, then hopefully you still have relevant experiences and interests to write about. If you don't, know that you'll be competing with upperclassmen, college grads and graduate students who do.
I'm not interested in your life journeys