Hi. This is my first guide, realy, first in my life. I'll present my own guid which checking well.
Jarvan i amazing!

Most people i've ever seen so far with jarvan are trying to solo, this is so STUPID.
Jarvan has 1 of THE MOST annoying ultimate during ganks/teamfights as he can basicly stop the retreat of certain opponents (given that they dont have blink/flash ready) and keep other opponents out during the fight.
Of course if you think your team can handle them all you might as well just use the ultimate so that it traps all of them.

Also, his standard gives a nice boost to allies and his shield's slow. This is so good when chasing down opponents or fleeing/helping an ally to flee.

Pro's:
- He isn't able to die fast.
- He can trap, stun and slow opponents very well so is usefull in teamfights.
- He can reduce armor by 10% with his Dragon Strike and his passive Martial Cadence deals 10% of the opponents current hp as magic damage ( max 400 damage ) on your attacks, this can only occur once every 6 seconds on the person you hit.
- Can escape very nicely as he has slow, his standard+strike, his ultimate and flash.

Con's:
- He don't make damage. He can only tank or support.
- Vulnerable to CC like fear or taunt.
- Can trap himself or allies with his ultimate if not used correctly which could result in angry looks >:( to you

You Should Startand 5xNext istoYou should buy boots(normal or mercury) to lvl 6-8, bacouse you need speed in ganging.
After boots you should buyto Atma later.
After you should buy mercury (if you didn't earlier) and maketoLater you have to endfor awesome damage from health.
The end of build is.

Optional Items:
- if your enemies are faster.- if your enemies make large dmg.- if you need more damage.