Jhin is by far one of the most fun ADCs to play (my personal favorites are Kai'sa and Ezreal) and he's super strong if you know how to play him! Although he's a very strong champion in every part of the game, there are also a lot of weaknesses that he has, but we'll be covering those in the later chapters. Jhin is the type of champion that has a very strict playstyle, and teaches players how to limit or control themselves, or encourage players to push their aggression to the edge.
Jhin is a pretty standard AD marksman, but in my opinion he is quite unique compared to champions like Ashe and Caitlyn. He has 2 abilities that are semi-global, a unique movement speed that can help you deal loads of damage while staying safe if used properly, and crazy amounts of spell-based waveclear for the laning phase.

I think the laning phase is the weakest point for Jhin. Taking into consideration the runes you use on him are mostly scaling, and that he is very reliant on damage items to burst with his R and auto attacks, the priority for Jhin players is normally to be even with the enemy, or ahead in terms of gold and experience. Farming with Jhin is very easy, because of your constant 4th-shot crits, dancing grenades and traps, starting cull on Jhin is not very easily punishable, and almost always guarantee that you are ahead in gold once the item is completed.

For lanes that you will get punished a lot for (e.g. Caitlyn), taking the Fleet Footwork keystone along with Doran's shield is optimal, but the sorcery tree can bring lots of benefits for Jhin in the later parts of the game. In winning or even matchups, like Kai'sa or Xayah, cull and Arcane Comet are the best runes to take. However, if you're against champions who plan on AFK-farming for the first 20 minutes like Jinx or Sivir, the best counter is to take Comet, Doran's ring and get lots of lane priority for your team. There are 2 main benefits to starting Ring: lots of extra mana sustain meaning you can push or trade more constantly, and having a 1-potion advantage that you can abuse AFTER trades.

After the laning phase, things get a lot simpler for you. You don't have to worry about going even if the enemy scales better than you. That's because of Jhin's late game peeling and setup. You should still be farming waves constantly, preferably in the safest lane to be in of the three, and be placing lots of traps in the jungle and in lane. They can give crucial vision, and a connecting W from you could mean a potential kill for your team! But, keep in mind that dealing damage in fights is still much more important than that cannon wave toplane ;)

In almost every fight, you have to make sure you can't get gap-closed on by any of their enemies. Jhin is very weak in 1v1 situations (unless you're incredibly fed, but that can't really do anything against their 7/1 leblanc) and until you're stacked with defensive items, you should not be forcing unwanted fights. Your ult and W are both pretty reliable and can slow down the enemy, from both short and long range. Before fights, placing traps around your team's possible flank positions is a
really good idea, because it can slow people down and grant you vision of them. During fights, if not using your ultimate, you should be focusing on NOT DYING while giving out as much damage as you possibly can. Because all of these rune pages include manaflow band and celerity, don't be afraid to walk up and use your spells.

People normally underestimate Jhin's ult, and its effects on the enemy team. It isn't an ability you should ONLY be using in teamfights, contesting objectives or catching enemies off-guard is actually a much better way to use Curtain Call, and seems much more useful when teamfight DPS is higher if you auto-attack the enemies instead. Another common problem is that people can't time their ultimates properly. Instead of spamming all four bullets as quickly as you can, holding your shots can actually make more of an impact. People will get more pressured by your ultimate, and might lose focus of other threats (like YOUR 7/1 leblanc!). One more benefit of holding your ult is reading the enemy's movement patterns, for better predictions.

Having played a little less than 50 games of Jhin this season, and maintaining a winrate above 60% for the whole process, this guide is the playbook I used. It's my first time making a champion guide, especially a specialized one, so please let me know how I can improve in the future. Hope you win games!!