Don't make these 5 biggest resume mistakes, say Harvard career experts—and examples of what to do instead

In such an uncertain and competitive job market, there's never been a more important time to polish your resume (even if you aren't on the job hunt right now).

Before you get started, take some time to think about your strengths, weaknesses and goals. Also keep in mind who your competition is and what unique skills you have that might set you apart.

Once you've given these things some thought, it's time for the most important — and perhaps trickiest — step: Putting it all on paper. Here are the five biggest resume mistakes to avoid (along with examples of what to do instead), according to advisors at Harvard University's Office of Career Services:

1. Spelling and grammar errors

If you want a professional job, write like a professional. Too often, people ignore the importance of spelling and grammar because the job they want doesn't involve related tasks like editing manuscripts or magazine features.

But spelling and grammar are indicators of two skills that are essential to any job: Attention to detail and communication. They tell hiring managers if you're diligent in your work and can communicate clearly — both verbally and via email — with co-workers, supervisors and clients.

Examples of common errors:

• Missing words. After rereading your own resume a dozen times, it's easy to miss missing words, like "oversaw team engineers" (when it should be "oversaw a team of four engineers"). Always ask a friend or someone you trust to check for these things before submitting.
• Writing about previous jobs in present tense. Generally, you should talk about old jobs in the past tense, and your current job in present tense.

2.  Using passive language

In a passive sentence, the object of the action becomes the subject of the sentence. If that sounds confusing, that's because it is.

Resumes written in passive language can make for a boring read, use too many words, be vague and, worst of all, lead to a tangle of prepositional phrases. For a stronger effect, career experts at Harvard suggest using an active voice and compelling "action" words:

Examples of passive vs. active:

• Passive: "...35% revenue growth was realized in our team over three years."
  Active (with action verb): "...team achieved a 20% revenue growth over three years."
• Passive: "...promotion to senior manager was given to me after only six months of working at the company."
  Active (with action verb): "...promoted to senior manager after only six months."

3. Missing or unnecessary contact information

At the very top of your resume should be: Your name (big and in bold), address (to let the hiring manager know where you're based), personal email and phone number (so they can contact you).

In some cases, it may be appropriate to include a link to your website or portfolio. Anything else is just a waste of space.

Examples of what not to include:

• Photo of yourself. Save that professional headshot for your LinkedIn profile, which the hiring manager will likely look up if they think you're a strong candidate.
• List of references (or note saying "references available upon request"). It's already assumed that you have co-workers and senior-level colleagues who will vouch for your skills. Most hiring managers will only ask for references if you make it to the final stages of the interview process.

4. Not well organized, concise or easy to skim

A black and white resume with clear headings and spacing will stand out more than a colorful resume with excessive use of boxes and line borders coming from all directions.

Make your resume easy to read and follow by balancing white spaces and using underlining, italics, bold and capitalization for emphasis. When listing details under a section, use bullet points (instead of numbers or letters).

Examples of bad formatting:

• Sentences and sections cut off. This often happens when you're converting your resume to a PDF, so make sure your formatting translated properly before hitting the send button.
• Confusing order of headings and information. List your "Experience" heading in order of reverse chronological order (most recent job first), and the details (i.e., tasks, accomplishments) of each job in order of importance.

5. Too long 

Unless you're applying for an executive position, your resume shouldn't be longer than a page (at most two pages).

Note: This does not mean you should abbreviate. Whatever it is, spell it out, or your reader will have no idea what you are talking about.

Examples of what will make your resume longer:

• Using a narrative style. If you've written the great American novel, put that on your resume — but don't turn your resume into a novel.
• Using personal pronouns. The hiring manager already knows the resume is about you. So instead of "I achieved [XYZ]...," just start with "Achieved [XYZ]..." Dropping personal pronouns will also make for a stronger and cleaner read.

Dustin McKissen is a career expert and founder of McKissen + Company. He has been named one of LinkedIn's "Top Voices in Management and Corporate Culture." Follow him on LinkedIn.

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