i play guitar and piano, i am writing a song for school, this got way to deep, i need ideas

I am inspiring this piece of music to be based off of a piano instrumental vibe. Some of the songs that have inspired me to form this kind of piece that I'm looking for are feelin blue by Soichi Noriki, detune by Takeshi Kobayashi, and the perfect pair piano Ver by peaceful noise. (apple music)

Lily chou chou is also another example of what type of music i am going for, because she got me through my middle school years lol, not that middle school work was hard but life around me was, and i just pushed things away with music.    This 'vibe' is important to me, therefore i want to make it pretty well done, and something that i can be proud of and show to people without being ashamed of anyone judging. I don't have a fear of people judging me, and i don't really get embarrassed lol.  

I also have a singer, and we are planning to get together soon. She is one of my good friends, if the song needs one she will sing, and is also writing it with me. I plan to make the music before adding the song, if thats what i should do, tell me otherwise. Still forming the lyrics as well. 

If anyone has any ideas on how i can accomplish this PLEASE comment, or reach out to me in some way, tell me chords to play or notes, and what the strumming pattern for guitar would be!