Paladin Holy Spells

Flash of Light - Heals a friendly target for X to Y. The Paladin is also good at keeping players alive. Use Flash of Light to keep party members alive.
Holy Light (Healing) - The Paladin is a good healer with Holy Light.
Divine Protection - You are protected from all physical attacks and spells for X seconds, but during that time you cannot attack or use physical abilities on yourself.
Divine Shield - Protects the Paladin from all damage and spells for X seconds, but reduces attack speed by X%. This replaces Divine Protection because it allows you to attack while active, unlike Divine Protection. You can heal yourself while using Divine Shield! This ability slows the Paladin's attack speed.
Divine Intervention - Sacrifices the caster to remove the party member from battle, shielding him from all harm but preventing him from taking any action for X sec.
Seal of Righteousness - Fills the Paladin with holy spirit for 30 sec, giving each melee attack a chance to cause X to Y additional Holy damage. Only one Seal can be active on the Paladin at any one time. Unleashing this Seal's energy will cause Z Holy damage to an enemy. Does holy damage on every swing. The Judgement effect is "Judgement of Righteousness" to differentiate it from the Seal damage in the combat log.
Seal of Light - Fills the Paladin with divine light for 30 sec, giving each melee attack a chance to heal the Paladin for Y. Only one Seal can be active on the Paladin at any one time. Unleashing this Seal's energy will judge an enemy for XX seconds granting melee attacks made against the judged enemy a chance of healing the attacker for Z. Only one Judgement per Paladin can be active at any one time.
Seal of Wisdom - Fills the Paladin with divine wisdom for 30 sec, giving each melee attack a chance to restore X of the Paladin's mana. Only one Seal can be active on the Paladin at any one time. Unleashing this Seal's energy will judge an enemy for 30 sec. granting attacks and spells used against the judged enemy a chance to restore Y mana to the attacker. Only one Judgement per Paladin can be active at any one time.
Consecration - Consecrates the land beneath the Paladin, doing X Holy damage over Y sec. to enemies who enter the area.

Retribution

Seal of the Crusader - Fills the Paladin with the spirit of a crusader for X sec. granting Y attack power. The Paladin also attacks Z% faster, but deals less damage with each attack. Only one Seal can be active on the Paladin at any one time. Unleashing this Seal's energy will judge an enemy for A sec. increasing Holy damage taken by up to B. Only one judgement can be active at any one time.
Judgement - Unleashes the energy of a Seal spell upon an enemy. Refer to individual Seals for Judgement effect. Judgements that place a debuff on their victim have their duration refreshed when the judging paladin strikes the victim with his or her melee swings. In addition, Judgements that place debuffs cannot be resisted. Using Judgement will initiate melee combat.

Protection

Seal of Justice - Fills the Paladin with the spirit of justice for X sec. giving each melee attack a chance to stun for Y sec. Only one Seal can be active on the Paladin at any one time. Unleashing this Seal's energy will judge an enemy for Y sec. preventing them from fleeing. Only one judgement per Paladin can be active at any one time.
Righteous Fury - Increases the threat generated by the Paladin's Holy attacks by X%. Lasts Y mins.

Undead Tools
Once you start seeing Undead monsters, make use of all the skills that specifically target them. These skills are available at the trainer. Ask around to find out where you can find Undead monsters.

Exorcism (DD) - This direct damage spell is good for finishing off Undead monsters or for "pulling" them. Also works on Demons.
Turn Evil - This causes the monster (undead/demon)to run away. This is good for multiple monster pulls. Pick one of the monsters that isn't being attacked and send it running away. You can then focus on the remaining monsters. This is also a good escape ability. Another use could be to send the monster running away and then heal yourself while the monster is gone. This has an increased chance of breaking early.

Lay on Hands (very long cooldown)
Uses 100% Mana. Heals a friendly target for an amount equal to the Paladin's maximum amount of health and restores X of their mana. Drains all of the Paladin's remaining mana when used. This is one of the Paladin's best abilities. Use this in special cases when you're about to die or to save a party member. Make sure you don't waste it; save it for when you really need it. Nevertheless, if you never use it, you're also wasting it.

Other Information

Divine Protection, Divine Shield and Blessing of Protection - Targets of these spells will receive the "Forbearance" effect, preventing another of these three spells from being applied to that target for one minute.