Hello guys. My name is William and i've been playing for quite a decent time (~6 years !). I've been playing Quinn since her release, but I think she got left behind the spotlight for Graves, Sivir or Lucian. However, since she got reworked for the Marksman Update, I feel like Riot gave her a second chance to shine. That's why I'm making this guide to help you play the (not so) new Quinn through this guide.
Be aware that this is my first guide, so it won't be as perfect as we'd like to. I must say thanks to jhoijhoi's guide, which helped me a lot, so thanks. I'm not an english native either, so tell me if I made mistakes ! I'll also update this guide and check your comments to help you and improve myself. Let's start !

Pros +Ranged Champion +Extremly High mobility with Vault and Behind Enemy Lines +Big burst potential with Harrier +Very nice poke with Blinding Assault +Strong Mid and Late Game

Cons - Vault can get you killed if launched badly -Squishy (that's why this guide is there!) -Can be out of mana very fast - Behind Enemy Lines can be denied very easily

: Quinn's passive, Harrier. Valor mark someone as vulnerable, which gives you bonus damage if you hit the target while the mark is active. This is very important to note that you have vision on a marked target, and that it will be disabled during your ult, Behind Enemy Lines

: Quinn's Q ability. Since the rework, it does not apply blind anymore ! [5.23 Update : It how applies a "blind" effect that will reduces the ennemy range.] However, it now marks someone as vulnerable, which means that it apply your passive, Harrier.
Note that her Q now reduces the main target's vision

: Quinn's W ability. This spell is very important because of the passive, which give you attack speed and move speed after hiting a vulnerable target. The active is interesting to check around your position, in case you wanna check brushes, jungle camps and more.
: Quinn's E ability. This is going to be useful in many ways. From slowing someone to proc Oppressor , to escape an ennemy or even engage. Be aware that engaging with Vault may put you in a dangerous situation.
: Quinn's R ability. Your fresh, new ult. Thanks to the low cooldown, you'll be able to roam, chase or even escape a lot more than before. Be careful because it has a 3-second channel time, and almost everything(except minions and jungle attacks) will make you swap back to Quinn, which also won't detonates your Skystrike !

---

[*] In this sequence, you want to start with your Q. This is your poke ability, as well as fast-pushing abitily it does great AoE damages. You also want to max it first because it provides high damages, not counting the fact that it also applies your passive Harrier into your Q's target.

[*] Then, follow up with your E. Why ? Into early game, it'll give you the opportunity to jumpinto your opponent to try a level 2 kill, or you can jump out of your opponent if he gets agressive, or if he get an early gank. You max it because you'll get a lower cooldown on your E, which is important so you can get Harrier faster, or simply because it's your main mobility skill ( Behind Enemy Lines is an high mobitity skill but you need to not get interrupted during the channeling or while flying)

[*] Finally, your W. You get it level 3 so you have that extra attack speed and move speed bonus after hiting a vulnerable target ( Harrier), as well as getting a huge-ranged vision spell to anticipate a gank (if the jungler hasn't showed up yet). Maxing it will also increase the move speed and attack speed bonuses you get from attacking someone vulnerable.

[*] Of course, you get and level up your ulti as soon as you can, nothing special there.

Let's get to Masteries.


FEROCITY:
~ for the 4% Attack Speed.
~ to get some sustain during laning phase.
~ to get lifesteal. The level 18 +10AD from Natural Talent won't be necessary.
~ to get a very nice roaming snowball effect.
Indeed, it says each unique champion, so staying mid won't increase the damages you deal.
Note that you can pick Oppressor to get 2.5% increased damage, which will be proc'd with your E, and any other CC coming from your team. However, you have to choose between 2.5% during a limited amount of time and an up-to-5% permanent boost.
~ for the free armor penetration.
~ to have even more sustain when you're running low into laning phase. It also gives some nice lifesteal into late game.

---

CUNNING :
~ to get a sweet 3% move speed buff while roaming.
~ to have more HP, as well as mana back, which is important since Mana pots has been removed.
~ to get extra damages on low targets.
~ is very important since it may save you from minions attack, ignite, poison...

ALTERNATIVE PATH

RESOLVE :
~ is an interesting late game choice when you get your defensive items like Dead Man's Plate or Guardian Angel.
~ is going to be nice at early, to roam slighty faster.
~Both and are good since you get lifesteal and/or health.
~Finally, so you can get your summonners spells faster.

---

To sum up, get 18 points into ferocity to have some very nice offensive bonuses, obviously. Then, you could go for Cunning which will be more offensive, or Resolve to be more defensive. However, I feel like Cunning tree is slighty better because of Merciless and Dangerous Game .

Now about the runes you should pick.


[*] : You're going to play AD and it provides a decent start (+8.5 AD at level 1).
[*] : It's the most effective flat armor rune, and it's going to help you resists slighty more.
[*] : It's the most effective flat MR rune. It's going to help you resist as well.
[*] Finally, to give you a little attack speed boost. However, you can swap them for AD Quints, to get an offensive early and get an extra +15 AD at level 1.

Now summoner spells :

Also, some people use teleport mid, but I find it useless to Quinn since your ult is going to be fast enough to go to any location.
"Most champions rely on Teleport to safely stray from their team, but League's speediest champion can move about freely and split push - or counter a split push - anywhere on the map without needing summoner spells."➤Rito said it, Quinn goes where she pleases.

Highlighted build :

[*] Let's begin with your starting items. They are two main choices that you could take : Going with Doran's Blade or Cull. Doran's Blade is a nice choice if you want to start with an extra lifesteal and health. However, after few tests, I'm now using Cull in 60% of my games because the extra gold gives you a big snowball potential
[*] Next is going to be your First back items. You want to have Vampiric Scepter after your first back so you get back to lane with even more life steal as well as getting your Mercurial Scimitar faster. Get some Health Potion back, except if you can buy your Boots, or even both.

Now your core offensive items.
First of all, Mobility Boots which will give you an insane movespeed combined with Behind Enemy Lines.
Next is the Sheen which offers decent stats, especially on-hit damages, which combines greatly with your passive ( Harrier).
Finally, Mercurial Scimitar which gives life steal now. This is a nice item because it will give you few resists as well as heavy damages.

Defensive items now.
Let's follow with Dead Man's Plate which gives you a nice movespeed boost (up to 60), not counting the nice +600health and +50 armor, which are pretty cool stats.
Then you have Maw of Malmortius which give you a fairly nice amount of AD and MR, as well as armor penetration, and a very cool +10% spell vamp and +10% life steal when dropping below 30% HP.
Build ending up with Guardian Angel, to get another +60 Armor and +60 MR as well as the "second life" passive which can drastically change a (team)fight output.

---

Optionnal build path :

[*] There is not so much to say about this path. Basically, you want to have the same starting items ( Doran's Blade➤ Vampiric Scepter+ Boots etc.)

[*] Depending on your progression, rush an early Trinity Force if you have enough gold for the move speed, passives, AD...etc., or get instead an Infinity Edge to have brute and early damages and crit chance.

[*] However, if you get few issues or you want to dominate your lane, you should consider going for the Maw of Malmortius instead, or the Mercurial Scimitar against AP champions with CC (Leblanc with Ethereal Chains or annie's passive Pyromania..etc.)

Early Game

In the Early Game, Quinn is a strong champion. She can poke her opponent pretty easily, counting on her passive Harrier and her Blinding Assault.

[*] To fully harass or trade against someone, wait for your passive to be around 2 seconds, then get closer to the ennemy, so Valor marks your opponent. Then Auto Attack to detonate your Harrier.
[*] Once you hit it,throw your Q, Blinding Assault, into your ennemy to deal damages and apply another mark so you can Auto Attack again.
[*] If you're level 2 or above, and you Auto Attack'd again, use your Vault to damage him a little, and apply the third mark so you can deal another boosted auto attack.
[*] Depending on how much you poked your opponent, you can :
-Try to finish him off to get an early kill with ignite and/or flash
-Disengage to wait the cooldowns, and do another combo to kill

TL;DR: Harrier➤auto attack➤ Blinding Assault➤auto attack➤ Vault➤auto attack

---

Mid Game

The Mid Game begins very early for Quinn. I think it starts once you're level 6 and you get Behind Enemy Lines. You'll be able to roam right away.
What you want to do, is pushing the wave to the ennemy tower, then ult :
[*] To your jungler's next location, so you can assist him and it becomes a 3v1 Top, or a 4v2 Bot, which usually leads to 1or2 free kills.
[*] Simply, where it's pushed. Even if it's warded, without boots, you'll be fast enough to get behind the ennemy and gank the top/bot.
Both thoses strategies will help you and your team get ahead in golds very fast.
Although there is a negative point :
Do NOT forget the ennemy mid ! This is a very common mistake. The ennemy mid may as well roam, or simply push and get free farm, or if you rush mid to fast, he may wait for you in the jungle.
Leaving someone without any opponent because you roam is double-edged.

---

Late Game

In the Late Game, you can are left two options : Splitpush, or "Teamfighting"
Let's get to Splitpushing :
[*] All you need to do is simply get on a free lane to push as far as you can. Try to buy few wards so you don't get surprised (2 second to ult). If you can, you can even splitpush between two lanes (Bot➤Mid or Top➤Mid) thanks to Behind Enemy Lines's move speed.
Splitpushing is pretty interesting only if your team is doing pretty great without you. Note that a lost teamfight by your team while you were splitpushing may lead to a lost dragon, baron, inhibitor or even nexus.

Then you can go with "Teamfighting" :
[*] This usually lead to win, however it gets complicated. Your job there is going to kill someone in the ennemy team before the teamfight (if you can, their ADC), like a Rengar would do. ➤ This solution is slighty easier if you get the Optionnal build, which gives your high damages.
[*] If their team are camping into their base, simply group up with your team before engaging. If you go with the "defensive" build, you can start the teamfight by catching someone up with Vault, which will also trigger your Skystrike. Try to catch up their ADC, and if you cannot, simply catch someone off position. ➤ Like I said, it would be easier if you got the build to engage so you can survive an lot more, while dealing a fair amount of damage

That was my Quinn Guide !

I hope that it will be useful to you, starting out the new season !
I've detailled few core points, trying to not make it too long.
I'll update it and answer your questions as much and as fast as I can, which means pretty much every two days.
I would very appreciate that you leave a fair rate. If you downvote this guide, please explain me why into the comments, so I can improve myself and the guide!