Hello guys, I've been veteran with Jarvan IV and I've almost never lost top (thank you for losing top stupid jungler with 0 ganks). I decided to make this guide in order to help you guys to learn how to play Jarvan IV.

For this build you will need following:
Medium amount of skillshot (his abilities aren't some hard to land)
Good ability to farm
Quick reactions

Pros / Cons
Pros
Has free armor and ATS from his E ability
Ungankable if played properly
Extremely tanky
Can deal good damage (especially with his passive)
Really good AD scaling on abilities

Cons
Can run out of mana if you spam spells too often leaving you vulnerable and easily gankable
can't think of anymore cons

Why maxing E instead of Q?
Because E grants you survivability. If your solotop opponent is someone like Rumble or Swain and if enemy team has jungler like Amumu then certainly max Q first.
I also max W last, why? Because it doesn't give too much shield and it scales only by amount of nearby enemy champions.

I take armor penetration marks and quints because most of champions don't have more than 25-30 armor which means if they don't stack armor at levels 1-3 you can practicly deal true damage with auto attack and Q
Seals - I don't feel like needing any more armor because of E skill
Glyphs - Really useful early-mid game especially if you are solotop against Rumble or Swain

Classical 9/21/0 masteries for tank.
If you are jungling, instead of magic resist and Initiator masteries take Tough Skin and Bladed Armor

These items allow you to be tanky, but still doing lots of damage.
First buy

Regrowth Pendant

and 1

Health Potion

If you are farming properly you should have enough gold for philosopher's stone around 3rd minute already. Also if you are having hard time farming don't buy Wriggle's Lantern, but in late game buy Bloodthirster. With Wriggle's Lantern AD champions shouldn't be of any problem anymore, now for tank items. Buy Phage and Giant's Belt, then proceed to Frozen Mallet, with its slow + your E+Q combo enemies are 100% dead if they try to run. Next buy Atma's Impaler. Who wouldn't want additional armor, crit (although in my opinion having less than 25-30% crit is just waste of money) and its passive? Now buy Chain Vest and Cloth Armor or even better, just instantly upgrade your Heart of Gold in Randuin's Omen if you have enough Gold. Last but not Least buy Force of Nature. Why? Health regen, movement speed and magic resist (did I mention it gives brutal MR?)! If enemy team has fed Mage/AP carry or fi they have 3 or more AP champions then buy Force of Nature before you buy Atma's Impaler. Also if enemy team has 4 or more (which I sincerily doubt they'll have) switch Force of Nature with Thornmail.

Also if you still have some money and time left in your current match, feel free to buy Bloodthirster instead of Wriggle's Lantern.

Tip: If you are having trouble laning buy Health potions, also buy wards before you get wriggle

For Summoner Spells I take Exhaust and Flash.
They allow me to easily catch fleeing enemies or escape from enemies when you are low HP.
If you feel you that you don't have much use of Flash or if your want to chase enemies on longer distances, feel free to take Ghost instead of Flash

I hope you guys liked my guide.

Feel free to write feedback, any additions and anything else you want to write.

P.S.
Sorry guys that I don't have pictures. It's strange but I don't know how to put them ;)