This is my first build that I am posting for Ashe. It follows some basic guidelines for her but also I throw in some items that will really help in mid to late game fights depending on how good you farm.

pros
you deal very good damage and at a fast rate, with the natural slow Ashe has you are deadly
can take down towers and other objectives quickly and get out before the other team can get to you
cons
the biggest con is you are kinda squishy for most of the game so if you push to far or get agrod by the other team you can go down fast that's why flash and heal are key abilities to this build
if you fall behind early you are down for, with this build it is best if you can go back and get the bf sword on your first back, if you die early it could devastate you for the game.

run down of the items and when to get them based off of what is going on in the game.

you get first blood,
this is the ideal way to start any game but is great if you can do it with this build since the first item you need is very expensive. start with the bf sword, and if you can pick up another item that builds towards infinite edge. with this scenario you are basically set to take on anyone early game since you are so far ahead on items. once the IE is complete move through the item list above in order and finish the build.

you don't get first blood but can farm very well and don't die
this is like you getting first blood but it will take you a little more time to get IE and your enemies will be more evenly matched with you. follow the same guidelines as if you got first blood

you are farming and die early
this can kill you in any game, falling behind early, but with Ashe it could basically end your game.

if this is to happen then you need to build what ever piece of IE you can build when you are back, also I like taken a few extra potions to keep me out longer to try and farm back to time lost while being dead. you will be behind but if you can keep your deaths to a minimum and your team is good by late game it won't matter that you were delayed with your build.

the worst thing to happen that will destroy this build is if you are constantly dieing and have no time to farm or if you have a bad support or just a bad teammate who takes your farm. this is a fairly expensive build and you need to get ahead early

while playing with other people I have noticed that morgana ashe bot is a very good combo as morgana can snare and you have constant slow and high dms. other champions that are good are braum, he can help if you every get to close, thresh kinda the same idea with him and his lanterns. and really any take support that can take damage if you need to get awsy.