This is a simple guide mainly made to show u the most basic things. I think the playstyle is different dependign on the champions you are facing.. So here I only show you what i think are the best Runes, Masteries, Items and other stuff for Yasuo.

Marks- Critical chance , this will help you do load damage early game because of the yasuo passive double critical chance ^^ and late game it helps u achieving almost 100% crit ( u get 97% with my recommended build)

Glyphs- Magic Reasist , Simple all around best glyphs for AD giving u a nice defense against all magic dmg.

Seals- Armor , Simple all around best seals for AD giving u nice defense against all AD atacks

I think the masteries are pretty much self explanatory.. anyway:

Block and Unyielding- Makes u receive less dmg from monsters and champs basic atks

Double Edged Sword- Gives u 2% more dmg

Fury- Gives u atack speed wich also lowers ur (Q) cooldown

Enchanted Armor- Since we dont get alot of armor and magic resist cause we yasuo isnt a tank, this helps alot in the overall amount of magic res and armor we get.

Veteran Scars and Juggernaut- This gives u more HP and also More dmg because we buy Atmas impaler more HP = More atk dmg ^^

Dangerous Game- When ur onto pentakilling youl see why this helps.. :D

Warlord- 5% more atack dmg

Frenzy- Yasuo is a Crit champ.. and this extra atk speed will make u atk faster and lower the CD on Your Q ability just awsome!

Devastating Strikes- More penetration, more Damage!

Havoc- 3% more dmg!

Executioner- 5% more dmg for lower HP targets!! this will help u finish ur enemies much easier!

Brute Force and Mastial Mastery- More atack dmg..

Boots- Best overall safe/agressive gameplay item more movement more possibilities of chasing and evading/running away!

Brawlers Gloves- With this and the runes i recommend you you will have 33%critical chance at lvl 1!

Avarice Blade- This is one of the best items for Yasuo, It gives u more gold from your farm and gold per second and gives u 10% crit change = 20% crit chance for yasuo and will later be able to turn into our Atmas Impaler ^^

Atack Speed boots- The atack speed will help u not only atacking faster but also lowers the cooldown of your Q!

Vampiric Scepter- To help sustaining damage and u get life from ur Q dmg too (on Hit efect atk) :)

Infinity Edge- This is defenitly the best item for yasuo and a MUST HAVE! This will give u 50% critical chance and 50% Criticals Damage wich helps you alot cause you will mostly do Crits and your crits do less 10% dmg this way u will be doing 252% Crit dmg because Runes 12%+ crit dmg 10% less crit dmg from yasuo crits( because they incrsed crit chance to double they nerf crit dmg by 10%) and 50% + crit dmg from the infinity.

Blade Of ruined King- This is an awsome item that will help you do more Dmg to tankier enemies, chase some1 by using its Active passive and by Will give u more atk dmg and atk speed that once again LOWERS YOU Q COOLDOWN xD

Giants Belf- Help u geting tankier and able to sustain more damage

Atmas Implaer- Giants belt followed by an Atmas impaler because the more Health u got the more Atack dmg u will get from atmas passive!

Frozen Malet- This is an awsome chasing item it will slow ur enemies so much they wont be able to escape you and also gives u lot more dmg due to more HP(atmas impaler +dmg) and more 25Atk dmg.

Maw Of Malmortius- the best Magic resist item for any AD champ in the game, not only it gives u magic resist but also a shield that absorvs magic dmg when ur lower HP and the Lower ur HP the More atack Damage u will have!

So in the end this is how this guide is though about:

U will have nice atack speed = more DPS and lwoer CD on your (Q)= even more dps

97% Critical chance= almost always critical atk

252% Critical dmg= All ur atks are crits and with this you will be doing Crazzy dmg!

Frozen Mallet, Blade of ruined king and Atmas Implaer- so your enemies cant run away from you, you get Awsome Life steal, Load more dmg cause more HP = more damage and blade gives u nice atk speed and dmg passive, nice defense of atmas together with 5% more defense from masteries and more dmg from 3%+ max HP from amsteries!

Maw of malmortius- Awsome magic resist and shield at lower HP and the Lower HP the more Damage u will do!

So imagine ur Dying u do more dmg and use ur blade of ruined king to turn the battle to your side.. getting more HP and still doing more dmg than normaly at higher HP! ^^ Just a simple example.

With this build you will see your self in situation u think werent possible for u to survive and win and do so! Sometimes even u will get like OMG how did i got to survive and win this 1 v 3, 4 ,5 ..

Anyway Guys Hope you Enjoy, if u liked this simple guide please recommend it, rank it up and show it to your friends! Before ranking this guide down TEST IT! You will see how damn good it is!