[OPINION] Tips to write a poetry book

Hello! I'm currently writing a poetry book as a graduation gift to my girlfriend (which would be this December). It is composed of 366 poems, each day of the year (Yes, even including Feb 29), and has a last secret unwritten poem hidden in each. Where the last poem has an exactly 366 letters and she should be the one to write it at the last page, hence the final line "You will always be the co-author of my life"

Can I ask what are your tips and tricks for making an ambitious book like this? I'm using ChatGPT as a writting assistant (only for prompts). I'm fairlynew to this but has been making poetries for the past 4 years being with her. Thank you in advance!