Martial Cadence[Passive]

Cooldown: 6 s (per target)
Innate: Jarvan IV's initial basic attack on a target deals [+8% target's current] (min 20) bonus physical damage. This effect cannot occur again on the same target for a short duration.

Dragon Strike[Q]

Cost: 45 / 50 / 55 / 60 / 65 Mana Cooldown: 10 / 9 / 8 / 7 / 6 s Range: 770
Active: Extends Jarvan IV's lance dealing physical damage and lowering the Armor of enemies hit for 3 seconds.
If the lance contacts Demacian Standard.png Demacian Standard it will pull Jarvan IV to its location, knocking up enemies in his path. This effect can be triggered even when immobilized.

Physical Damage: 80 / 120 / 160 / 200 / 240 (+120% bonus)
Armor Reduction: 10 / 14 / 18 / 22 / 26%

Golden Aegis [W]

Cost: 30 Mana Cooldown: 12 seconds Area of Effect: 625
Active: Grants a shield that absorbs an amount plus [+1.5% Jarvan's max] damage for each nearby enemy champion for 5 seconds, and slows surrounding enemies for 2 seconds. Base Shield: 60 / 85 / 110 / 135 / 160
Slow: 15 / 20 / 25 / 30 / 35%

Demacian Standard [E]

Cost: 55 Mana Cooldown: 12 seconds Range: 860 Area of Effect: 75 | 600
Passive: Gains Attack Speed.
Active: Throws a Demacian Standard to a nearby area dealing magic damage to enemies. The Standard lasts for 8 seconds and grants surrounding allied champions Demacian Standard's passive Attack Speed. Passive Attack Speed: 20 / 22.5 / 25 / 27.5 / 30%
Magic Damage: 80 / 120 / 160 / 200 / 240 (+80%)

Cataclysm[R]

Cost: 100 / 125 / 150 Mana Cooldown: 120 / 105 / 90 s Range: 650 Area of Effect: 325
Active: Heroically leaps to an enemy Champion dealing physical damage to nearby enemies and creating an arena of impassable terrain around them for 3.5 seconds.
Activate again to collapse the terrain.

Physical Damage: 200 / 325 / 450 (+150% bonus)

Ganking

You can be very creative in your gank pathing with Jarvan and you can start ganking as soon as you hit lvl 2. It doesn't mean you should gank, but you have the option to. Because he can dash over walls, you can dodge enemy wards and gank from unexepected areas which can surprise enemies and net you a kill or summoner spells.
Lvl 2 ganks are much more effective with Red Buff because your auto's will slow the enemy and burn them for true damage
Starting the Oracle Lens is very beneficial in clearing wards and seeing whether or not the enemy knows you are in the area.
Tip:
If you're behind the enemy, don't waste your Demacian Standard and Dragon Strike to close the distance but instead start walking at them and autoing them. If you have Red buff , they will get slowed and slowly start dieing. Only use your gap closer after they flash to close the distance. Your Golden Aegis is also a small slow which can also hinder their movement.