Novice Guide:
Once you achieve a certain level of ability and experience you may advance to a higher class through the class transfer system.
To accomplish a class transfer you must fulfill a class transfer quest. These quests can be undertaken by characters of level 19 and above. After fulfilling the quest and achieving level 20 or higher, class transfer can be completed. At the time of class transfer you will choose one of many available professions. Once you made, your decisions is irreversible. Make your choice carefully.
I know all of the teachers in this area for any profession you might choose.
Human and Elven Fighters train with Grand Master Rains of the Fighters Guild.
Human and Elven Mystics are taught by High Priest Raymond at the temple.
Dark fighters and Dark Mystics go to Grand Master Tobias of the Dark Elf Guild.
Orc Fighters and Mystics are taught by High Prefect Drikus.
Dwarven Fighters are trained by Warehouse Chef Rikadio at his warehouse or Head Blacksmith Mendio at his blacksmith shop.