Hi there. You need to pick all the right choices that help improve Akira/Arane's relationship through Akira's story.
Feel free to join our Discord and check the guides channel for more details on that.
So it's not the right choices in terms of what raises Akira's friendship level.
It's the right choices that better improve the relationship between Arane and Akira, there's no visual indicator other than reading each option carefully and picking the one you think it improves their relationship.
Feel free to join our discord as someone has written a guide for it in the Guides channel.