You can explain to a potential employer why you are the best candidate for a job by discussing your accomplishments, showing your enthusiasm for the job and giving specific examples about your experience and skills that make you the best person for the position. Be specific but brief, and avoid long-winded answers.
A job interviewer asks a variety of questions to find why an applicant is best for the job and to narrow down the best choices available. The interviewer may ask you specifically why you're the best candidate for the job, and highlighting actual accomplishments achieved in your career can help sell your reasons. The interviewer may also want to talk about tasks that are similar to the tasks involved in the open position, as employers often want to find someone with prior experience.
Potential employers are generally impressed by details applicants provide based on how they helped to improve things at previous jobs. Provide examples of what you have done to increase customer service, sales or productivity in the past. Candidates who can demonstrate positive ways they've handled issues can leave a lasting impression on potential employers. You can provide examples of problems that came up and how you solved those problems.