Have a character reach IC Alchemy Level 4, you can only do this with Michelle as the other characters are already Level 4.
When you reach Port Zala on disc 2, buy blue berries from Faina.
Now make Blue Berry Potions until you reach IC Level 3. (2 Blue Berry = 1 Blue Berry Potion).
Go back to Faina and buy yellow berries.
Make Yellow Berry Potions until you reach IC Level 4. (2 Yellow Berry = 1 Yellow Berry Potion).