Hi people :)) I'm an unranked Xayah main, that love this champion a lot. I don't have sooo much maestry points (43k), but I know about this bird. this is my account - https://br.op.gg/summoner/userName=Phanpy950 (I'm BR)
I will update this guide every time I find it necessary, so check it from time to time so you don't miss it ° W °

Xayah isn't the srong champ she was some time ago, but you can still do a lot with her ( If you play correctly ). She´s a late game hypercarry with a decent laning phase, can also peel for herself with R and E X P L O D E anyone with a good E. Also unstoppable when fed. If you have the Star Guardian skin, she also has the best voice lines in the game.
Pros
High DPS and burst, insane wave clear / teamfighter (lots of Aoe damage and CC), selfpeel with R, decent poke, great all-ins, strong late-game
Cons
struglle against really agressive lanes, requires good positioning, because of feathers and the fact that you are squishy, immobile, even with the R, that also has a loooooong cooldown (more than 2 minutes), requires time to do maximum damage
The key point to playing well as Xayah is patience. Patience to scale, to accumulate feathers, to wait for your CDs, especially ultimate's.

Passive
CLEAN CUTS
After using an ability, Xayah's next basic attacks will hit all targets along their path and leave a Feather. This is an essential part of Xayah's kit and her main way of accumulating feathers on the ground. You can poke your enemy by auto attacking a minion, and then the feather pass through the minion and hit him. Masterize this for regenerating mana whith presence of mind.

Q
DOUBLE DAGGERS
Xayah throws two damaging daggers that also drop Feathers she can recall. Useful for poke with Q+E, but most useful to activate passive and put feathers on the ground. If you go presence of mind, Q regenerates your mana.

W
DEADLY PLUMAGE
Xayah creates a storm of blades that increase her basic attack speed and damage while granting her movement speed if she attacks a champion. This helps you a lot when trading in lane. W has a long cooldown so don't use for nothing. If you AA and use W when the projectile is on the air, the extra damage will activate so use this to not lose feathers from your passive.

E
BLADECALLER
Xayah calls back all her dropped Feathers dealing damage and rooting enemies. Obviously, Xayah's main source of damage. This turns you into the terror of the teamfights, but you always need to keep an eye on the feathers (one eye on the bird, the other on the feathers).The damage multiplies based on your crit chance, by half of it. For example, if you have 80% critical chance, the damage from the feathers is 40% higher. E + flash or E + galeforce (YES) is possible to take someone by surprise. Really funny one-shot capacity. (q + e when the feathers are in the air for poke, but passive AA + insta E is not possible)
Burst example:
https://youtu.be/2MitzN7hQOY
R
FEATHERSTORM
Xayah leaps into the air becoming untargetable and throwing out a fan of daggers, dropping Feathers she can recall. Amazing outplay tool. This skill is what I love more on this champ. Use the R to dodge the main cc ability or one that will do a lot of damage. You can also use it aggressively, but it has a higher value in a defensive way. Only use it that way if you want to root more than 3 people.
Examples:
https://youtu.be/olEwsyn8ahY <- E + flash included here https://youtu.be/GEjoGbh2Q30
COMBOS
FIRST OF ALL. Remember: always AA when you can to make use of your passive.
Poke
Q+E when the feathers are on the air. Nothing much to say, here's the video. https://youtu.be/lAjQSKv5TIM

Instaroot

This combo was very powerful and get nerfed. It is not so good, but you can still do this. Consists in Q+AA+E, or even W+AA+Q+E (use E when the Q's feathers are on the air for an unexpected root). Nice for CC lock and for short trades in lane.
https://youtu.be/NjRIObeso0E and https://youtu.be/KqcvTGUjt_0

"The boom"

Q+R+E. I call "the boom" because you can explode anyone or/and demolish the teamfight. Cancel your Q's animation with R and then call your feathers back for tons of damage. Before using this, consider what I said in the explanation of the R.
https://youtu.be/aPddEi-1vhY

Feather bombing

Root the enemy, activate W and AA him as much as you can. Q+AA+E+W+AAs, Q+R+E+W+AAs, any form of root is good. Maybe this is the real Featherstorm.

Xayah don't have much combos, just remember to vary between AAs and abilities.
Here is E+flash/E+Galeforce https://youtu.be/GrXNC4E50pE and https://youtu.be/1ByKDs8qqGg

PRECISION- Lethal Tempo x Fleet Footwork
For Xayah, take lethal tempo. It gives you attack speed, that helps you trade in the early game and also maximize your hypercarry capicity. You can also activate it very easily with Q and extend the duration with your passive. Fleet footwork is possible too, but I tested and I don't liked it, principally because the attack speed of the lethal tempo is needed. Take fleet footwork if you are going to be bulied under your tower by both ADC and support.
Presence of Mind
With E.R. "nerfed", this is a must have. AA a minion with your passive to regenerate mana if you hit a champ.
Legend: Bloodline x Legend: Alacrity
You can use both one or other. Sometimes you will not build attack speed until your 5th item, and sometimes this hapens with lifesteal.
Cutdown
In this preseason the tanks are really strong, and this can help you. If there are none or few tanks you go Coup de Grace.
SECONDARY- Sorcery x Inspiration x Domination
Sorcery- More damage and/or MS.
Inspiration- More gold and sustain.
Domination- More healing and/or more cooldown reduction for ult.
I recommend taking Sorcery, with Trancendesce/Nimbus and Gathering storm. I know that Inspiration is good too, when you need sustain, but im using Domination these days in all my games as Xayah(ToB and Ultimate hunter). The games have been very short these days, so i stopped using sorcery, and domination helps you in the whole game, while inspiration is very focused on lane and sorcery a lot in the late game.
Being able to use the ult much more than before is unexpected and funny

Doran's blade/Doran shiel/Cull
Normally, you start whith doran's blade. Against hard poke (like Caitlyn and Brand) you can start doran's shield or even cull for a very passive lane.

Mythic options

This is the most important part of your kit. Go Galeforce for having more scape and mobility (you can do E+Galeforce just like E+flash so I pretty like this).
The Imortal Shieldbow is going to be nerfed surely, the shield and extra life per legendary item is just so good. Go this in most of situations, for more survivability.
You build Kraken slayer against lots of tanks, but this is the worst of the three adc items.
Eclipse is nice for duels, gives you a lot of damage, MS, shield, but you miss AS. Take legend alacrity.
Draktharr duskbade is possible, not good. The AH and invisibility are nice, but don't compensates.

1st item
The Collector - gives you burst, good againt squishy targests and for snowballing
Essence reaver - gives you mana sustain and A.H, good for long trades
Stormrazor - AS, damage and slow the enemy, good when the lane is easy / enchanter enemy, something that you can "farm" if you slow then down
Infinity Edge-- This is a necessary item for the crit users. Increases your damage a lot.
Others

Laning
As i've said, Xayah is a late game hypercarry, but you you can absolutely dominate the lane, based on how well you control your feathers.. That's how I win most of the games (games, not lanes). AA on different angles with your passive to cover ALL the lane with your feathers. Then, the enemy will be zoned away, and if he pass in front of them, or RIP enemy, or he will take too much damage and have to cast a spell. Against hard lanes, stay safe and farm with Q and E.
Mid game
This varies depending on your laning phase. If you:
Won lane - In this point you must have 2, 2 + 1/2, which is a considerable spike for you. Play agressive, but not sooo much, go for teamfights, stay with your support and be careful if your ult is down. Farming is important, try to keep the average of at least 10 cs per minute, the game is still not won
Lost lane -
Tie - If the enemy bot lane scales more than you, you should have won the lane. Buuuut you can still win, if you farm/or kill the enemy a lot. If they don't, you're doing well, keep farming and don't die a lot, until you get your powerspikes :)
Stomp
Late game

-Never stop moving, so you will make full use of your passive;
-Don't waste your R for nothing and be careful when it's on cooldown;
-If you have your R up, you can bait the enemy to engage in you and then just kill him;
-Try to walk to the sides to hit a enemy when they are close to the feathers;
-Always try to leave at least 1 feather on the enemy's foot, for zoning or damage if he ignorates it.

Level powerspikes- Level 3, 6, 13, 16. In level 3 you have your 3 skills learned, and with this you can trade. For the love of God, don't trade with somethig like Draven or Lucian. In level 6, obviously, you get your ult, that is very powerful. Level 13 is when you maximize your W' level, together with E and ult level 2. And 16 is when you maximize your ult's level.
Items powerspikes- 4 and 5 crit items/100%/80% crit (principally because of the Navori Quickblades and your E), core build/3 items + boots. You get stronger and stronger as much as you get your items.

Thank you for reading:)) I will add more things here, continue checking constantly
Plz
And leave a like if you can, it's free and make me happy OwO

Put your suggestions on the comments (ou se vc eh BR pd me adicionar msm, o nick ta lá no início), I am also making a guide for Taliyah, and maybe I'll make one for Senna/Ashe/Kai'sa when I learn more about these three, so check it out
If you want
Se vcs quiserem, eu também posso traduzir o guia inteiro p português, so pede ae nos comentários ou na minha conta :3

S2