Here is the full list of all 50 Persona 4 Golden achievements. It takes around 150-200 hours to unlock all of the achievements on Windows.
Earn all trophies
Register 100 Skill Cards
Hear 250 of Rise's navigation lines
Complete the Persona Compendium
Perform 50 Persona fusions
Defeat Margaret
Switch Personas 5 times in 1 battle
Read all books
Max out all Social Links
Rescue Marie
Create Izanagi-no-Okami
Visit Nanako in the hospital 3 times
Defeat The Reaper
Max out 10 Social Links
Register over 50% of the Compendium
Experience a fusion accident
Use 4 or more Personas in a special fusion
Catch the Sea Guardian
Get 50 Sweep Bonuses
Make 5 perfect boxed lunches
Buy 5 things from Tanaka's Amazing Commodities
Swing the net with perfect timing
Buy a special croquette from Sozai Daigaku
Win a prize from the vending machine
Win the Miracle Quiz Finals
Defeat Izanami
Buy a Persona from the Compendium
Secure Tohru Adachi
Deal over 999 damage in 1 attack
Rescue Nanako Dojima
Finish Aiya's special dish
Max out all social qualities
Rescue Naoto Shirogane
Go to 3 movies at 30 Frame
Secure Mitsuo Kubo
Rank #1 in your class on an exam
Drink the coffee at Chagall Cafe
Max out a Social Link
Enter a special relationship with someone
Rescue Rise Kujikawa
Perform 50 All-Out Attacks
Defeat a Golden Hand
Buy an item from the Capsule Machine
Rescue Kanji Tatsumi
Exploit enemy weaknesses 100 times
Register a Skill Card
Rescue Yukiko Amagi
Fight a battle in costume
Enter a battle with Player Advantage
Obtain the Persona Izanagi