For his incomparable skill with the bow and his unquestioned sense of honor, Varus was chosen to be the warden of a sacred Ionian temple. The temple was built to contain an ancient pit of corruption so vile that Ionian Elders feared it could envelop the island in darkness. Varus prided himself on his position, as only the most exceptional Ionian warriors were selected for the role. He lived with his family in a nearby village and led a quiet life of disciplined routine until the day the forces of Noxus invaded Ionia. Their shock troops left nothing but death and desolation in their wake, and the temple lay in their path. Varus was forced to make a decision. He was bound by honor to stay and defend the temple, but without him the village's few inhabitants could offer little resistance against the oncoming war machine. Gravely, he chose to fulfill his duty as a warden. The corruption could not be allowed to escape.

His arrows sundered the troops who tried to wrest the temple from him that day. However, when he returned to the village, he found that it had been reduced to a smoldering graveyard. Remorse at the sight of his slain family gave way to overwhelming regret and then to seething hatred. He swore to slaughter every Noxian invader, but first he needed to become stronger. He turned to that which he had sacrificed everything to protect. The pit of corruption would consume him wholly, as a flame devours a wick, but its abominable power would burn within him until he was lost. This was a path from which there could be no return. With grim resolve, he condemned himself to the black flames, feeling malevolent energy bond to his skin...and with it, the promise of ruin. He left, seeking the blood of all Noxians involved with the invasion, a grisly task that eventually led him to the invasion's most infamous perpetrators in the League of Legends.

''The life of an arrow is fleeting, built of nothing but direction and intent.'' - Varus

I've been playing Varus a lot lately trying out different builds and this seems to be the one that works best. I've been getting on average 15+ kills a game and 2v1 at any time and if there's a tank 2v5. This build give you a lot of attack speed so you stack Blight fast. You don't really have to Q because Varus auto attacks do 800 static damage. Its almost impossible to 1v1 him. His Q is really good for when there getting close or running away for all the burst damage.

Runes vary on Varus. You can do the static armour pen with AD armour and magic resists. Or you could do what I do. I use full ad runes except for my armour runes. Its always good to have extra armour when your bot lane because your facing another ad ranged, so he will do less damage to you. The runes in this build are a safe and good way to build Varus.

The masteries in this build are top notch XD. These masteries gives Varus max damage and more HP at the start. Making Varus a less squishy at the start of the game.
Instead of getting the HP down in column 2 you could go down into the 3rd tree and get the Buff duration spec. Its also good but the extra HP and Armor imo is always better.

I love to start boots and 3 HP bot as any ranged ad carry. Its always good because just in case you take some harass you can just use a HP pot and heal back up. Also the boots are always nice for chasing someone for a kill. Then I get the B.F Sword to give Varus a lot of early damage and then turn it into the BloodThirster so that it stacks off all my kills and gives Varus life steal so you dont have to B so much and you can stay in lane and farm. After BloodThirster I start my Phantom Dancer because Varus need some attack speed for good harass. Also it applies the stacks of Blight a lot faster which means you can Q for max damage. Then after I stack another Phantom Dancer because its not only good for Varus's damage but its also good for his life steal when you take AoE damage from team fights. After that you get Infinity Edge making you almost unstoppable and Guardian Angle because your a squishy AD ranged carry.

As Varus you always want to try and harass early game with your Qs. His Q has such a big range that you don't have to be anywhere close to them to get some good damage in. I like 2 start out with 3 basic attacks as Varus to stack up his Blight then Q them so it explodes his Blight and does max damage. Also Varus's E (Hail of Arrows) also explodes the Blight stacks that you apply on the target so in case you miss you can always get your Blight to explode for extra damage. His E is used for when ever you want to drop an AoE slow and when facing a champion that heals, remember that his E also reduces healing taken by 50%. His ultimate is pretty sick. You don't want to start out with Varus's ulti unless you pick someone off. Always wait till the enemy team is just a little bit stacked up because when your through your ulti in it can spread to the enemy team and snare them all. Very good for team fights to make it spread on them all!!!!

Although Varus is very OP damage wise he is very squishy. For summoner spells you always have to have flash. No matter what, because Varus has no shock back or anything to get him away from people. I like to follow up Heal or Exhaust. Heal is pref because it heals the user for a lot and its very good for 1v1. Also when you take some early harass its always nice to trick your enemies that your low and use heal and your back to full. Exhaust is also very good, it can slow your enemy and you would have no problem landing your Qs and AoE slows for when your Exhaust is about 2 run out.

Pros

-Very good early game harass
-Very good sustained damage
-Has a large range on his Q (Main burst source)
-Hits really hard late game

Cons

-Very Squishy
-Q can be silenced
-Ultimate has a large range but small radius

Varus has a really good passive for when creep farming and getting jungle buffs.
Living vengeance- will give you 20% attack speed if you kill a minion or monster, and 40% attack speed if you kill a champion.
Minion kill:3 seconds
champion kill:6 seconds
What I when I'am farming lane is go after a full HP minion if I have the buff then switch to a LOW HP minion and get the attack speed bonus so you always have it on you.
When getting Red or Blue bluff this is very use full. Always start with your Q then an hail of arrows that should kill 1 of the small minions then switch to the main guy but when your buff wares off from your passive switch back to the small minion and then get back on the red/blue buff. This allows to get blue/red faster because you always have the 20% attack speed and this means you CS more!!!!