Vagrant - When you'll first enter Madrigal, your first job is Vagrant.

Skills: Clean Hit, Flurry, Over Cut

First Job Class

At level 15.

Acrobat

Acrobats are those who mainly wield long distance weapons such as bows or yoyos. Using the skill tactics of speed and accuracy, they are usually able to break anyone willing enough to fight them.

Sly and witty, the acrobat is a cunning trickster.

Bow Skills - Junk Arrow, etc.
YoYo skills - Slow Step, Crossline, etc.
Universal skills - Dark Illusion, Acrobats

Assist

Being an assist, you'll be able to choose to either be a fighter, or a healer. If a fighter is what you desire, assists generally favorite is close and personal combat. As you progress, you will find that using certain skills you will be able to destroy all enemies at once. If supporting other characters is more your style, you may choose the alternative. By using a magic stick, you will be able to cast magic spells to enhance the abilities of those around you.

Buff skills - Heap Up, Beef Up etc.
Attack Skills - Straight Punch, Burst Crack etc.

Magician

Magicians are ranged spell casters, they are able to focus large amounts of magic upon an enemy, dealing a great deal of damage before they are even reached. Magicians generally have lower defense, lower HP, and sometimes even delay when it comes to casting spells. However they are able to cast spells that not only damage enemies, but slow them down as well.

Magic Skills - Mental Strike, Rooting, etc.

Mercenary

Mercenaries prefer to partake in close range combat. The main characteristics of this particular class involve physical strength, and a strong body that is able to withstand attacks.

Powerful and headstrong, the mercenary has both inner and physical strength.

Mercenary Skills - Keenwheel, Sword Mastery, etc.

Second Job Classes

At level 60.

Jesters

Jesters focus on ranged attacks using Yo-Yos. They have a wide range of skills that allow them to be strong PvP'ers with their YoYo attacks, use some of their penya to do increased damage, and escape incoming attacks. Some Jesters will attack using a Bow, taking advantage of a Jester's trademark 4x Critical Rate.

Ranger

Rangers are a ranged based melee class that focus on using bow skills to damage enemies. Coupled with the Dark Illusion Acrobat skill, Rangers can make a great PK support class as enemies will be silenced, and will not see you attacking, or leaving the scene of the crime!

Billposters

Billposters are undoubtedly the most self-sufficient class in the game. With their normal assist buffs, and their additional damage skills upon second job change, they are a very strong class. They are more of a melee class, and fight using a knuckle and a shield.

Ringmaster

Ringmaster is the other class that an assist can choose from. When it comes to partners, this class is the most sought after due to their ability to enhance others abilities and skills. With extra buffs and skills, this assist class is almost considered a necessity for game play; or, at least, they make it easier.

Psykeeper

Psykeepers are one of the Magician's second classes. These, however, do not deal in the field of elemental damage. Most of the attacks, which are very powerful, tend to be based off mental and demonic forces.

Elementor

Elementors are a second class for magicians and are a high damage spell casting class that uses staves to cast devastating elemental spells. They have a wide range of elemental skills at their disposal which can damage one or several enemies at the same time, as well as self buffs to increase the damage they deal.

Blades

Blades are a second class for mercenaries and are the best damage dealers in the game. As a blade you will be able to wield two weapons at the same time and thus drastically increase your damage output.
Knight

Knights

Knights are a second class for mercenaries and are the best tanks in the game. As a knight you will receive more health points per stamina point than any other class.


-Short guide from Flyff Wiki.