Let’s start with the easiest remedy to optimize your resume.  Word documents are notorious for losing their formatting.  ATS’s often struggle to process them.  The result is that your word resume looks terrible.  This makes it hard for the ATS to locate key words.  The chance that the ATS chooses your resume is low.
On the other hand .pdf files retain formatting no matter what type of computer or ATS the hiring manager is using.  Before you apply to a job take a moment to convert your .doc file to a .pdf first.
2.  Mirror the job description

ATS are very helpful but they are not smart.  They can only seek exactly what the recruiter told them to find.  Use the exact same keywords that are on the job description.  Ultimately, this is the best chance of getting noticed.

For example, if the ATS is searching for ‘human resource’ experience and your resume lists ‘HR experience’ you will be passed over.  It’s a good bet that the recruiter will enter the search terms into the ATS in the same way that they are written in the job description so study the description and mirror it everywhere possible on your resume.

3.  Include the title of the job you want

Since an employer is searching for something specific one of the very first keywords they use is the title of the position they are trying to fill.  If they need a product engineer they will certainly include ‘product engineer’ in their search criteria.  So if you aspire to be a zookeeper, make sure your resume contains the word ‘zookeeper’.

4.  Don’t Over Do It

Don’t try to fool the ATS.  If you list a strong keyword more than 3 times on your resume you are risking rejection by the software.  An ATS will most likely disregard your resume if it has more than a 95% match to the job description.

5.  Minimize Graphics

Graphics like charts, profile pictures or logos used to be a great way to dress up a resume.  Today, it’s better to remove them.  ATS’s are getting better at recognizing graphics.  However the best you can hope for is that the ATS will ignore the graphic rather than getting hung up on it.  Your best bet is to remove any graphic you don’t feel is necessary.  They may be pretty but it won’t matter if you never get a chance to interview.

6.  Keep it Simple

In days past some resumes were more like a work of art.  Ornate graphics, multiple fonts and colors helped to make the document stand out to the person reviewing applications.  Creativity does not impress an ATS.  To keep a simple resume, don’t add more than two colors and avoid mixing fonts.

7.  Use Traditional Section Headers

ATS are good at identifying info contained in common sections of a resume.  If you use traditional section titles like Professional Experience, Education, Skills and Contact Information the ATS is sure to pick it up.  Even better is to capitalize all section headers.  ATS put more emphasis on capitalized words.

8.  Functional Job Titles

Unique job titles like ‘Digital Dynamo’ or ‘Chief Inspiration Officer’ are fun and show personality, but software isn’t seeking a fun personality.

The ATS will understand your resume if you use a more traditional and functional title.  Therefore, ‘Digital Marketing Associate’ and ‘Director of Marketing’ are smarter choices.

9.  Also optimize your resume for the human eye

After the ATS selects your resume, a live human being will review it.  A person will see the document much differently than the software.  Therefore, a resume should be relevant easy-to-read and in a format that will please the human eye.