In order to identify your real needs and concerns, ask yourself: "Why do I want what I want?". You will then quickly realize that you have good reasons for wanting what you want.
A practical example.
What I want (position):
- Either I get a 7.5% salary increase, or I leave!!
Reasons why (your underlying interests):
- „One of my colleague and I are doing exactly the same job. I have noticed that he is getting 7.5% more then I do! For me, it's an issue of equal pay for equal work.“
- „A salary survey which I've seen recently shows that I should earn 7.5% more. For me it's important to get paid in line with the market.“
- „Due to inflation, my costs of living have increased by 7.5%. For me it's important to maintain my standard of living.“
Do not take a position. Write down your underlying concerns, needs and interests, and explain them during the meeting.