Although it is essential to benchmark your salary precisely, don't aim at a specific colleague's pay. When you make direct comparisons with coworkers, you show a lack of ethics and maturity, hindering your chances of successful negotiation.
You may say it has come to your attention that others receive higher pay for doing the same job, but don't be aggressive or demanding. Remember that this argumentation should be about no one else but you and your contributions and value to the organization.
Rules to remember:
✓Consider your employer's perspective when thinking of why certain pay decisions have been made
✓Think of ways to mend the gap if a pay raise isn't immediately possible
✓Try to get an explanation from the Human Resources Department on your company's pay scale bands
✓Don't name your high-earning coworker during your salary review
✓Don't stay in the job if your employer refuses to pay your market value
Source: Harvard Business Review, 2016.