Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
I like to use this build for Ashe, especially when I teem up with a Soraka. If I get the farming done right early with a few kills sprinkled in I can rain chaos and destruction late game. Works on a Miss Fortune as well, but I've not tested that as thoroughly.
As far as items go, I buy the first four in parts. I aim for the boots first to ensure survivability, followed by a Medal of Valor (Part of Stark's Fervor) for HP. Then I go for the Tear of the Goddess, ensuring I have few mana issues for the rest of the match. Finish off these items and then get a Zeal, then Phantom Dancer. At this point the vamp form Stark's combined with attack speed lets me play somewhat aggressively.