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