Well, i won't and i can't speak much, english is not my language so please, get me a break about gramar mistakes.

I'll just explain you guys why do I play sivir like this, lets begin.

The 2 Doran Blades are optional, sometimes i buy 2 of them sometimes just 1, it really depends how is the game going.

After that the most important thing is (for sure) some damage, BFS should make it more easy for you to lane in an insane way, upgrading it to bloodthirster will only make you even more durable in lane, don't forget to get as much minians as you can.

When you play Sivir you must always look to more and more damage, that's why you need to get an Infinity Edge as soon as possible, run for it and you'll see the diference, when together with the last atack item, Phantom Dancer you will truly understand the meaning of IE.

My last 2 items, when i get there, are normaly Durability Items, Banshee's Veil is just amazing, together with Sivir "E" you can cancel 2 spells instantly, thats so usefull in team fight...
Warmog's to take the last space will turn sivir and amazing off-tank champion but still with tunes of damage, that will be powered up with the masteries:

23 - 0 - 7
Not usual right?
Also, my choises in that can depend, if i'll play ranked probably I change them for some off-tank masteries, but in some ordinary match this is awsome, get just the improval of Flash, Time Spent Dead and Mana Regen and put all the other points in offensive, normally I get full critical and atack speed (to stack with my item choise) and I take the rest when its more needed, everything that improves damage is good to sivir and don't forget to take "Demolitionist", Sivir is an amazing pusher, you have to deal a lot of damage to turrets in order to help your team!

Well, that's my opinion about Sivir, hope you like it, don't forget to vote :D

King Rewards,
iZho