Employers often ask a question like "Why should we hire you instead of the other candidates for this position?" as a way to discover the strengths of an interviewee.   Since you will rarely know the strengths and weaknesses of the other candidates, this question is really just an opportunity for you to convey what qualifies you most for the job.

Compare Your Resume to the Job Requirements

The first step in preparing an effective response to this type of question is to carefully analyze the qualifications for your target job. Review the job advertisement and also check the job section of the employer website where there might be a longer job description.

It’s actually a good idea to do this before you apply for a job. That way you can tailor your resume and cover letter so they are as close a match as possible to the job. 

List the Employer’s Job Requirements

If the employer has provided a detailed list of their requirements and preferences in the job description, then you are ready to proceed to the next step.  If not, then search Indeed.com or SimplyHired.com by similar titles and look for ads which clearly delineate what employers are looking for in candidates for those kinds of jobs.

Another way to gain a clear sense of employer preferences is to conduct informational interviews with professionals in the field to get their view of what it takes to be successful in that type of role.

Also check the skills required for the job. 

List Your Qualifications for the Job

Make a list of the key qualifications for the job which you have uncovered through your research.  For each item on your list, review your own work, volunteer and academic history to determine how you can show evidence of that qualification. Write down an example which shows how you have employed that strength to your advantage.

Why You Should Get the Job

Be prepared to describe the situation, project or challenge, actions you took which showcase the asset and any positive results. Your assets can be skills, areas of knowledge or expertise, personal qualities or relevant areas of experience.

Select 5 - 7 of your strengths that correspond most closely to the job requirements, and use these as the core for your answer regarding what distinguishes you as a candidate.

You can add a couple of your other special qualities which have generally helped you to be successful in productive endeavors and you will be ready to impress your interviewer.