This Build is all about Sivir and how to use her to her full power. I decided to make this build after competing in a tournament and win first 2 games and making it to third round with nice scores. Also not many Sivir builds so I will try and fulfill. Lets hope Right in.

Pros:
High Damage
Late Game Champion
MANA SHEILD OP
once Vamp Great Sustain
High Burst

Cons:
Squishy
Not a super strong early game
Mana Shield is glitched to hell
Mana Shield doesnt stop gap closers like leona's

Marks: For marks I like to take armor penetration to help do damage early and late game to tanks and carries.

Seals: I take Armor seals just to help with any enemy ADC and block the damage to later out tank there ADC.

Glyphs: I take scaling magic resistance to help with any APC and even most supports or ADC's.

Quints: I take Lifesteal Quints to help with sustain in early game and it will help in teamfights later to have about 25% Lifesteal.

Ok for masteries im going to get alot of comments about this but hear me out. So for Masteries I like to go 21-0-9 I take as much damage as possible for Offensive. In Utility I like to take movespeed and health regen plus the potion increased duration along with the biscuit because everyone wants that buscuit :3.

Bloodthirster: YES get this on Sivir ASAP this is not optional except if you take BORK but I would not take it over this as of now.

Beserker's Greaves: So for boots these I would primarily take due to them fitting into Sivir's play style. Merc Treads are the only other shoes I would consider.

Static Shiv: This is an amazing wave clear item but most people would say what about Phantom Dancer Sivir already can wave clear easily with her W but the think even though Phantom Dancer gives more stats the passive of Static Shiv is just as good.

Infinity Edge: Always get this item I recommend this on every ADC no exceptions I can remember at least :3.

Last Whisper: I take this all the time on Sivir due to the armor pen. and the ad isnt bad.

Black Cleaver: I wouldnt use this item but that doesnt mean its not good. It is a nice item but the 35% armor pen would help out against any super tanks if they all dont build armor get this over Last Whisper.

Guardian Angel: Commonly used item for everyone good for revive I take this almost every time on Sivir.

Banshee Veil: Good against any ap heavy teams but you already have a spell shield.

Mercurial Scimitar: Great item due to its AD and MR get if they have AP heavy team.

Fleet of Foot: This is great for chase having red buff makes this passive godly also getting a trinity wouldnt be bad for this but still I dont think trinity as a good item for her (I will test this later)

Boomerang Blade: This ability should always be maxed first for its high damage and its low cooldown. Boomerang Blade is a great CSing ability and the poke is great. Try and line up both directions of this to maximize damage.

Ricochet: So This is an amazing farming skill due to its potential to hit every minion in a wave and also works really well with static shiv. This also once you have your ult gets a speed buff on how fast you attack.

Spell Shield: Ok so this is the one mechanic on sivir YOU DO NOT WANT TO MESS UP. When you are playing up against alot of diffrent characters try and make them blow a heavy cc or if you need mana damage on to this spell because it neutralizes most CC (Riot Plz Stop Leona grabs). When Grabed by a support such as leona let her pull to you then use spell sheild to block her Q stun. This ability turns fights around.

On The Hunt: This Ult is a really good teamfight ult which can help you escape from most fights or engage on many fights.

For Summoners The two I take mainly is Barrier and Flash.

Ghost: Good with Sivir's Ult but really flash I find more useful.

Cleanse: Nice summoner for cc But you have a Mana Shield so you block alot of cc.

Teleport: Uhhhh? I dont take this on adc's use to its Usability changing alot during game.

Heal: Great for low Levels but after the nerf Meh.

Others I wouldnt take since the others are more for other roles or are just flat down useless.

Early Game: Just try to last hit as best as you can. Use Boomerang Blade or Ricochet If you have to to CS but early game isn't Sivir's Peak.

Mid Game: Once you get static shiv Taking a Minion wave should only take your Ricochets and the static shiv to kill it maybe Boomerang Blade too.

Late Game: Farming is so easy at this point on Sivir just like most adc's. Just attack and you should just one shot most.

Thanks for Reading the guide for Sivir I Havent decide who i will do next but it will come soon I will come back once I have a better understand for making builds and add Visuals Thanks For your Time and See ya Next Time :D.