well i build ashe with lots of attack speed for a couple of reasons. 1 when you pair attack speed with madreds bloodrazor you can put out some really good dps. Alot of teams now have 3-4 heavy tankish melle champs with lots of hp, which makes the bloodrazer great for chipping away at it. 2 being able to hit with your frost shot quickly can really help you and your team control the fight.
start with a dagger and hp pot. try and save your first hit for a champ. don't waste it on minion if you can help it.
next around lvl 6-8 you want to turn the dagger into a berzerker greeves and if you have enough money build a stinger. stinger is vital for this build cuz it gives great atk spd and cool down reduction which ashe needs desperately.
once you have your stinger you want to get your zeal. now your attacking like crazy and you've got some more run speed.
no you want to start your madreds. depending on how things are going you also might want to pick up a vampiric scepter. if you start with madreds razors you can easily take blue buff and you should be able to leave frost shot on and not loose mp which is great.
once you have your blood razor it kinda depends how then fight is going with what you would want to do next either finish your phantom dancer or build starks fervor.