Here is the full list of all 22 A Kiss For The Petals - there are Maidens of Michael achievements.
Complete the Mai/Reo route.
Complete all routes.
Successfully conduct Shizuku and Eris's graduation ceremony.
As Reo, socialize with the other Best Couples at Rena's apartment.
Complete the Shizuku/Eris route.
Propose to Eris.
As Shizuku, decide on a college to attend after graduation.
Complete the Nanami/Yuuna route.
Complete the graduation album.
As Nanami, celebrate Christmas privately with Yuuna.
Complete the Kaede/Sara route.
Join Sara's model unit.
As Kaede, talk with Sara about her career path.
Complete the Takako/Runa route.
Entrust Takako with taking care of Runa.
As Takako, help Runa and Rena mend their relationship.
Complete the Risa/Miya route.
Convince Miya to reconcile with her parents.
Confess your true feelings to Miya.
Have your first kiss with Miya.
Successfully host the Christmas Festival.
As Risa, win the Best Couples election.