It's my first guide and I decided to begin it with Varus. I like it and I think that my guide will be good for you. Enjoy it.

I decided to take armor penetraion runes to make more damage in beginning, because ad runes and worse to make more damage from auto attacks.
I took mana regen yellow runes, because if I want to stay on lane more I should have more mana.
Blue runes attack speed are very important, because if I want more damage, I should have more attack speed:)
Quintessenses are armor penetration to add red runes.

First page is standart for ad carries. 6 masteries in second page are to increase my defense. And 3 masteries in 3rd page are to decrease the time of death.

1st ability is the main for AD. It makes the great damage and it have very big range, we should take it first.
3rd ability hs second place, because it takes ad and it makes big damage, slow enemy.
2nd ability is for ap Varus and we don't need it first.
Ultimate can immobilize our enemy, but it makes ap damage.

We take Flash to junp and kill somebody or to save ourselves.
Ignite we take to reduce heal of our enemy or to kill the target.

First I take Doran's blade to take ad and health. We take boots to increase our movement and attack speed. We need to increase our attack speed and we take Zeal. Then we need AD - B.F. sword and then Bloodthrister is the best decision - AD and lifesteal. Then to make more damage we should take infinity edge - crit and AD. Now we need to take some more attack speed and we take phantom dancer. We are AD carry and we have low hp, because of it we shold take it - Frozen Mallet, hp, some AD and we can slow our enemies. And finally to increase our attack speed and attack damage we take The Black Cleaver - armor penetration, attack speed and AD.

Then I want to say that I did penta with this build and I think that u'll do it too. Good luck and enjoy it:)