Hello and welcome to my way to play Master Yi he's a really basic fun tanky dps champion and most of the builds,building him really squishy that way he is more kill 1-2 guys and then die well i don't like that playstyle at all so i decided to show to the community how to kill everyone and not to die.
I will be covering alot about the build and my own playstyle warning tons of text.

Pros + Tanky DPS :) + Stable Damage + Gap closer :) + Alot of resistance thanks to Meditate 300 MR and Armor when used + Attack speed steroid and Attack damage steroid + Can't be slowed + Amazing skins + Easy to understand and master + Can attack twice thanks to passive + Highest movement speed in-game (330)

space

space

Cons - Focused on teamfights because of the damage - High cooldowns - Not real escape tools if you are stunned or snared - Various counters - Medio-core farm - Low health for melee - Melee

• greater quintessence of Desolation: I like this quintessence becuase it is huge amount of armor pent,it will help deal more damage later and destroy armor items like Thornmail
  it will help you deal in lane and jungle true damage! It also works really great with Wuju Style.
• greater mark of Desolation: This is great bouns to your quintessence's.
  
• Greater Seal of Armor: This can null desolation quints and marks.
  Allows you to recive less damage in trades and in teamfights basiclly this is such useful seal for small price of ip.
  
• Greater Glyph of Scaling Magic Resist: I like to take this since there's always at least one caster on the enemy team,you want to minimize thier damage Especially later in game since they are more Dangerous later that's why i take per level and not flat i don't think that pre levels 9-8 ap casters dealing much damage

Offense
Summoner's Wrath 1/1 Since we take exhaust and why not to upgrade it.
Brute Force 3/3 +3 AD is always good helps to master yi's ad steroid.
Alacrity 3/3 +4% Works very well with your's Highlander and ad steroids.
Demolitionist 1/1 We can deal much more damage to turrets and backdoor faster i see no reason why not to take this.
Weapon Expertise 1/1 This adds even more penetration and this time 10% :).
Havoc 3/3 Allows you to dish much more damage in %'s also enchants Alpha Strike and Double Strike.
Deadliness 4/4 This gives you extra attack damage by level this is very nice late game and adds you even more damage.
Lethality 1/1 This is very awesome mastery it adds you more 10% critical damage with Infinity Edge it is 260% damage on each critical strike.
Sunder 3/3 Even more armor pent very good for master yi.
Executioner 1/1 I find this mastery very helpful when 1v1'ing or in team fights when you need to kill quick low health targets,Very helpful for last hitting early game as well.i see this mastery essential for master yi.

Utility
Good Hands 3/3 10% Less death time is very good early.this is very essential late game when respawn times are long
Improved Recall 1/1 Reducing the time on recall is very nice can save you some time when someone trys to interrupt your recall in the last sec with this you will be there in no time :)
Swiftness Even more chasing/escaping speed for master yi.

Boots-I like to with since this builds later into very useful item for master yi.
This allows you to dodge many skillshot and thanks to this you could buy 3 Health Potion
Which is very good for master yi since his health regeneration isn't the best.
And you dont really need anything else to start since you will have by level 2 Gap closer and AD steroid that means you don't need to start with any hard boosting item.

Wriggle's Lantern
After we bought boots this item for just 1600 can help you ALOT since you want to go solo top let's start with that this item gives you 30 armor which is going to help you to soak more damage and better trades.
23 Attack damage which is very good it helps you with last hitting and dealing more damage,15% Life steal which i find very useful since you going to have high damage thanks to Wuju Style and the 23 attack damage itself from the item.
This allows you to 1 hit creeps for 20% that means better farming and 500 to buffs or dragon which is great,This also gives you a ward that lasts for 3 min this means thier jungler won't able to gank you and you won't need to worry when someone didn't called "MIA".

Mercury's Treads-I like these boots since they have 25 flat magic resist which will help you alot against thier ap this gives you more speed and less crowd control effects duration which is very helpful when they have heavy cc team.

Phantom Dancer-One of the most known items for master yi since it is so amazing for him.
This offers for him the highest amount of attack speed, movement speed and critical strike, all in one item. Master yi using all of these status and makes the best of them like no other champion you can't go wrong with this item.

Warmog's Armor One note before buying this. get the Giant's Belt first
Now this item give when fully farmed gives 1270 health that means more 24 damage thanks to your Atma's Impaler first of all the health it gives is just huge it is one of the reasons why you want this!but that's not all you also get 40 health regeneration per 5 which is excellent with the mass health.you should get this quickly.

Atma's Impaler Now this is a real item one of my favorites first of all it gives you 45 armor protecting you from thier ad carry or caster then it gives you 18% critical which helps your auto attacks deal much more damage but wait that's not all!
The best part of this amazing item is the fact it transfers 2% of your maximum hp into attack damage!1k=20 attack damage with this build you will have 3.4k at the end that means 63 attack damage this works greatly with Highlander, Wuju Style, Phantom Dancer, Wit's End, Warmog's Armor

Infinity Edge - This item resembles attack damage champions and you can see why right?
This item gives huge amount of attack damage (80).
This gives 25% critical strike chance which is very good for you auto attacks but this works with the AMAZING passive this item gives. it gives you more 50% critical strike damage which works VERY WELL with your's Phantom Dancer, Atma's Impaler, Wuju Style, Double Strike
Also It is one of the most cost-efficient items; for just 375 gold you get 10 AD (based on the longsword price that would be worth about 280 gold), 7% critical chance (around 300 gold, based on different items) and the 50% critical strike damage passive.

Bloodthirster Ok so now it is probably end-game and you deal chunks but want more? sell that Wriggle's Lantern for this first of all this item got 25% lifesteal and 100 attack damage and i think it is ridiculous the base stat are 60 ad and 15% lifesteal but after farming 40 creeps it will give 100 ad and 25% lifesteal it is lost on death but common you are so tanky and you won't die ;)

Double Strike (Passive):I find this passive really working well with your Highlander or Phantom Dancer since they give attack speed which helps you proc this.High attack damage works with this very well too since this allows you to do two auto attacks and not one.
Overall this is very nice passive that helps you dueling and benfiets from your build and Skills as well it proc on turrets. Alpha Strike: This is the main AP-Yi Skill but this build isn't about ap yi.
This allows you to farm really well since it can proc 400 extra damage to creeps.
I like to use this as farming tool or/and as gap closer it does its job wonderful for master yi.Overall this skill really helps you whether if it's chasing a champion or farming. Meditate:This helps you when you are really focused by the enemy team and you need heal since this gives you alot of Armor & Magic Resistance and a 4.0 Ap ratio heal 700 Flat at level 18 without ap which is very helpful for tanking or needing a heal
Overall i like to use this as a shield like hourglass this helps you to stay in lane too but it dosen't really helps you other way so get this last. Wuju Style:I feel like this is the main master yi AD skill it gives you a huge boost when it is passive or active (35 passive level 5 skill/70 Active level 5 skill). It allows you to build attack speed early on and worrying about attack damage later and that's why we max this first. Highlander:This is a really amazing boost if you are chasing or being slowed or escaping or trying to duel this is really your bread and butter skill
It refreshes it's own cooldown every time you kill a champion and assists refresh it by half
This is very nice skill to backdoor as well.
And Highlander removes Nasus' Wither attack speed debuff as well as the movement speed debuff.

Exhaust
Reduces a target's Attack Damage by 70%, Ability/Item damage by 35% and slows its Movement Speed by 40% for 2.5 seconds.
This is awesome spell it can disable damage output completely. works well if they have fed carry it is also good for escaping or chasing
Flash
Teleports your Champion to target nearby location under your mouse cursor.
This is a very awesome spell it allows you to escape from jail or heavy situations or to chase even better

Wolves>Blue(Smite)>Wraiths>Wolves>Red Buff(Smite)>Gank/Golems>Ganks or jungle.
Play Video

Thanks to jhoijhoi for the line dividers/separators/Templates :).
Thanks to LoLWikia for few facts.
Thanks to Stonewall008 for his amazing route&jungle video.

So this is the end of my Master Yi guide hope you learned alot about him and how i play him :) Here are my scores (Sorry i don't really have any olders one :( )
Note that 2nd game the upper one they had 4 ranged dps we had none (stupid normals)Snow ball hard in jungle kids(2 ganks can make you snowball)(Win btw).