Learn the raw power of your passive when you have 100% crit and a lot of attack and movement speed.

More or less a standard AD build. I go scaling CDR over MR since you can get enough MR from items you could buy later (also we're in a heavy ad meta currently).

As the note said, standard adc masteries with your choice of keystones. DO NOT GO FERVOR OF BATTLE. You dont have the speed to use it properly.

You need 4 crit items at minimum to get 100% crit. Boots are not necessary because of the movement speed buff from Warlord's Bloodlust and the % from items. I usually get Duskblade because it helps with kill securing since you only have 4 shots. You should crit for over 1000 every auto after you get 4-5 items (depending on what your build looks like). I recommend getting Essence Reaver first for the 20% Crit and CDR.

You're going to want to play it safe for the first 7-10 minutes. Kill if you can, but dont put yourself at risk of dying. Simply forcing the enemy ADC to recall is a win for Jhin.

Once you have your first item finished, you can and should try to get either bot turret or help get mid turret.

Your ult can kill neutral camps including Baron and Dragon.

Your ult can NOT activate its on hit effect with neutral camps including Dragon and Baron.

Boots early on is ok. But they should be swapped out for your 6th item.

When laning always keep one trap on hand so you can use it in a fight. By itself any champion can walk out of its radius without taking damage. so wait for an engage to use it, and throw it a little behind them too.

You dont have to use all 4 shots. If you can't use them effectively then cancel early for reduced a CD timer.

Pros:

massive damage output
extremely long ranged ult
great aoe damage
every 4th shot is an execute
can hard carry a game
easy to acquire assists and kills
can lock down his own targets by himself

Cons:

very squishy
low mobility
long reload
4 shots, so pick your targets wisely
does not come back from behind as smoothly as other champions
locked base attack speed
will be focused in fights

Goes good with:
[*] Thresh
[*] Karma
[*] Leona
[*] Morgana
[*] Alistar
[*] Shen
[*] Blitzcrank
[*] Braum
[*] Sona
[*] Nami
*More or less anyone who has good, hard cc (AOE preferable) and can either peel or absorb damage.

Goes bad with:

- Soraka is ok but she does not provide that hard cc unless they stand on her e, she cannot be a tanky damage absorbing wall of meat, she does not have any engage, yes her heal's are great, but she does not provide much of an offensive threat while you reload.

- Tahm Kench is a good wall of meat and has hard cc, but he struggles with Jhin because he needs to hit an enemy 3 times to lock them down or eat them. He is good if you can communicate well with him. but more often than not I find that he just ruins your combos by either eating the target or eating you when you get low but could have killed them with one auto or one last ult shot. He also is very slow, having 2 slow champions in one lane is bad news.

- Janna does nothing in terms of offensive boosting to jhin that his passive already does. Her kit makes landing his w harder if she ults, and her knock up, while effective is all she has in terms of poke, which Jhin needs so he can combo with his w. Janna also has the risk of ulting the enemy onto Jhin which = instant death.

Use your 3 shots to lower the minions to near death. The use your q to finish them off because it does increased damage if it kills a target which would damage a champion more. Save your 4th shot for as long as possible if you can poke. Your abilities reset its duration timer fully each time you use one so dont feel pressured to quickly get it off.