References. It is assumed that you have references if you have previous employment history. It is not at all necessary to include “references available upon request”, adding this is actually a potential deterrent. Potential employers will ask you for your references later on in the interview process if they see fit. Of course, if references are asked for within the application process, provide them - just not on your resume.
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.