Hey All,
Thanks for checking out my build/guide thingy. This is my first build/guide thingy so Do leave comments.
And by no means do I consider myself "Pro." I'm an awesome ashe, and I made this build and its worked out extremely well.

The masteries I chose are designed for a more offensive/ cooldown reduction. If you spam Volley 3 times, and each hit does say... 300 damage, then its better than using Volley one doing 500 damage. Plus, with the attack and magic penetration added in, it can do some serious damage.

The build is pretty situational. ALWAYS start with philosophers stone, as it gives great regen for early game, saving money on potions. Plus the money it gives really helps push the build along. Berserker's greaves is great with the added attack speed. People say boots of swiftness, but honestly, Zeal makes up the difference just fine. Then add in the phantom dancer then you get all the speed you need, plus a bonus attack speed. Catalyst comes next, but at this point it becomes situational. If you need more health and magic resist, go straight for a banshee's veil. If you don't need it to much, then skip right to a Infinity Edge. Usually go for the balance, a catalyst then Edgee then veil. Infinity Edge really let's you hit hard. This bonus from the critical strikes really does damage against tanks, and will absolutely own low resistance characters. Then two Phantom Dancers are really just icing on the cake, you could also go for a Bloodthirster (Selling the philosopher's stone), which is a load of fun.

Volley is your bread and butter. It's great for annoying early game, and slowing down people to. Frost shot is great for chasing- and escaping if your fast enough. Hawkshot is okay, but the main reason to get it is the gold bonus. Your ult, Enchanted crystal arrow, is amazingly good. Its one of the few (Probably only) ult that can reach across the entire map. It does some pretty good damage, and the stun is nice, its great for catching people off guard, and ganking early game.

I pretty much made these up on the spot. I'm not very good with runes (I'm completely ****.) I just put in the top three things that Ashe likes: Attack speed, Critical Strikes, and Attack Damage.

Preferred: Flash and Ghost. Ashe has no escape spells, and stuns and slows usually deny your speed. Plus, they're great for chasing down people.
Okay... Clarity, Fortify, Ignite. These three are okay... clarity can help with early game mana problems, Fortify is... well Fortify. Ignite is good if you don't feel like chasing somebody down.
If you do I swear I will [Insert Threat Here]... Clairvoyance, Exhaust. YOUR ABILITIES COVER BOTH OF THESE, hawkshot for clairvoyance, Frost shot AND Volley for exhaust.

For the most part, Ashe can dominate the mid lane. Though there's always certain troublesome characters.
Teemo can do some amazing damage a lot quicker than you can. Don't engage until you have your ult. Stun him and go to town.
Caitlyn has better range spamable abilities than Volley, be careful and never stop moving. Try to avoid engaging until you have Phantom Dancer.
Annie is so annoying. She can really pound your health down. Stay back and if she uses her ult... run.

Ashe is a great character. She's extremely easy to learn, but if you want to be pro with her, it takes time and patience.
Also, Ne perdez pas de tir givre sur sbires, or I will find you.

-Fengi.