This is my guide for Jarvan IV my favorite champ and one i've had most success with. I hope this guide will help you accomplish the same.

Runes are pretty standard

Red - Armor Pen

Yellow - Armor or if you want Health Per Level

Blue - Attack Speed or if you want Magic Resist

Quintessences - Health or if you want Armor Pen

21 9 0 are what i take but these can be played around with to your liking.

Items i use can swap out the aegis to a randuins or GA whatever you like. But build above is just mine you can play around with different items to find your favorite and always change around for situational items.

I take Ignite Flash but these are really choice tbh.

With jarvan solo top is your best option you can mid, but top is much better. so early on just farm until about 5 or 6 once hear you can start harassing so you can either just poke with your Q or you can do your full combo E Q W smack smack smack or if for kill E Q R W smack smack smack, also you need to be keeping track of your opponents flash, if you want you can ulti too get there flash down and then coordinate with jungler to get the kill. So yea laning pretty self explanatory.

Jarvan is a great initiator with ulti and E Q combo, so usually just jump on squishy with ulti or knock them up to initiate.

So Thats it hope it helped if not hope a different one did.