Think of a resume as “self-advertisement” that sums up your experience on one page. Your resume is one of the most important pieces of your job application. It gives the hiring manager an overview of the qualifications you have for the job for which you’re applying. You should also familiarize yourself with the difference between a resume and a cover letter.
When writing the descriptions for the jobs you’ve held, focus on what you accomplished in each position rather than what you did. Listing quantifiable achievements in a numerical manner (increased sales 20%, reduced expenses by 10%, for example) will help your resume stand out.