Here are a few justifications you can use to justify a raise in your pay. You can use these points to promote your special value to the company.
- achievements in the past year within your work objectives
- achievements in the past year outside your work objectives
- extra responsibilities added since last salary increase with reference to your job description
- new qualification earned since your last increment
- new initiatives you plan to take on to enhance work efficiency and effectiveness, improve business competitiveness and profits, and reduce cost.
Try to quantify the results in each category as much as you can.