Here is the full list of all 30 How To Date A Magical Girl achievements.
See the Bad Ending
View Yui's secret event
Complete Yui's route
View Rei's secret event
Complete Rei's route
View Kaori's secret event
Drink a potion
Complete Kaori's route
View Hikari's secret event
Complete Hikari's route
See the Mystery Ending
See the Happy Ending
View Miyu's secret event
Complete Miyu's route
Reject a girl's confession
View Rei's friendship event
View Yui's friendship event
View Kaori's friendship event
View Miyu's friendship event
View Hikari's friendship event
Get an A grade in Magic
Get an A grade in all key attributes
Win a prize at the arcade
Get an A grade in Alchemy
Play with Hoshi
Get an A grade in Perception
Get an A grade in Expertise
Finish reading 6 books
Give a gift to a girl
Start out life as a Liar