This Varus build focus on getting in and out of fights fast and easy, while also putting out tons of damage.
I go 21/0/9, getting all the Attack damage, attack speed, life steal, minion damage, armor penetration in offense. while getting the mana, mana regen, flash cool down, and 2 in movement speed in utility.
Boots of Speed with 3x health potions---> Berserker's Greaves and Vampiric Scpeter---> Wriggle's Lantern and Wards---> Phantom Dancer----> Blood thirster----> Last Whisper---> Infinity Edge---> Sell Wriggle's Lantern and get either a Frozen Mallet or a Black Cleaver. Get Frozen Mallet if you are being focused. Get a Black Cleaver if other team is building a lot of armor.
Get your Q first, then get E next, max your Q by level 9 while getting your W at level 4 (for easy farm and harrass) while getting your R at levels 6,11,and 16.
Always last hit. so going down the middle lane or Bot lane with a tank or support is best for farming.