Here are the methods to obtain all the 4 Occult Fan mags:

OF 1- Search for this magazine in the shelves of the Balamb Garden library where the girl with a pigtail is. It might take some time. It can also be purchased at the Esthar book shop.

OF 2- Defeat the pub owner at Dollet in a card battle. Go to his room and repeatedly read the notes and magazines. Then check the old pile of mags there. You'll get a random item. Do it repeatedly to receive the OF 2. Purchasable at the Esthar book shop.

OF 3- When first arriving at Fisherman's Horizon(FH), in the screen where the elevator leading down is,look closely for a ladder. Go down the ladder and follow the path to meet Master Fisherman. Apologize to him to receive Occult Fans vol.3. YOU CAN ONLY OBTAIN IT HERE AND NOW! You can also get a Megalixir from this quest. Talk to Master Fisherman again and meet his student by the docks. You should talk to the boy 3 times to get 3 different events. After meeting Mayor Dobe, go back to the docks and get a diffrent event again. Talk to Master Fisherman again. Choose to meet him at the inn. Go to the inn and follow him out. Choose to accompany him a little longer and then choose to go by yourself. He should then give you a Megalixir.

Of 4- First ime you visit Esthar, talk to Presidential Aide near the air station when you are told to explore the town. Go back to the Palace and talk to Presidential Secretary. He'll leave and leave behind the OF 4. YOU CAN ONLY OBTAIN IT HERE AND NOW!

Courtesy of: Crystal Creator(i.e. me) at FFVIII PSX