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