Hello i'm studying Management and i came across an exercice where i need some help, thanks a lot

You will have a meeting with your manager to discuss your new salary. You have overachieved the goals this year and now is the moment to convince him that you deserve more than last year.

-You are in a very special moment of your life, with one newborn baby so you need to have more flexibility and you are willing to ask for a home office, 2 days per week as well.

-You know from other colleagues with the same position as you, they had increased 20% of their salaries. For you this rate is lower than your expectation.

-You need an increment of 40% (Last year they promised 30% and you got 25%) and one of your main interest in this negotiation is the flexibility to work at home to get more time with your new baby.

question:

-What are your personal and possible options to create value in this negotiation?