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