Introduction
Since I played ashe in the first tutorial i just love her.
I hadn´t been pretty good with her in the first games but after hundred of games with her I started to undxerstand how you got to play her...
I decided to tell you beceause the league of legends server are BUSY at the moment :D
Well... lets start!

Ashe is pretty hard to play in the early game beceause you got mana problems if you spam your volley.... Try to cast your volley just once in every level up to level 6...
if you are levl 6 there are two possibillitys :

First one is starting an atack with your ultimate you can flash towards your enemy and cast your volley... your enemy will get sunned longer if your arrow is flying an longer way..
thats what you can use flash and ghost to.. if your volley hittet your enemy he will get slowed thats the right moment to activate your frost arrows so he will stay slowed all the time.
If your volely is ready again do it again :)
he wont be able to escape and you will kill him / her

The second possibillity is to wait untill your enemy is pushing and shooting or hittting your tower.. if you git a little bit training here it will work better ...you shoot your ultimate so that your victim is stunned in the tower range and the tower is shooting at him / her you cast your volley to slow your enemy into that range...
enable your frost arrows to hold your enmy in the tower range longer just keep shooting at your enemy to kill him / her

Ashes ultimate is great to open team fights i cant help you here but i can tell you that you should try to hit the low HP enemy champs or anybody whos running out of this group of champions to stun him / her and your team will do the other work...
I had seen so much ashe players taht doesnt spam there ultimate.. but thats WRONG thats why ashe is one of the best mid chars you got to level fast to activate your higher level more additional effects or stronger effects runes
you got to "spam" your ultimate in every situation you think its intillegent and your team could need it.. if anyone escaped with low live do your hawkshot to find him/ her and shot your ultimate.. its no problem if it doesnt hit beceause your ultimate will be ready again in a couple of seconds.. :)

Okay lets start with the Pros and cons

you are dealing hard damage
you can stun your enemys every couple of seconds
you can stun your enemys every couple of seconds and win team fights that wise
you dominate mid and late game


Cons :You are pretty squishy that means if the enemy team got somebody who can stun and he hits you the whole enemy team will atack you and you wil ldie in 3 seconds...
(its possible to buy warmoks instead of shadow blades)
You are very weak up to level 6 or 7

Okay thats what we want to do ...
turn cons into pros or learn how to play with them
turn pros better into "super pros"

You can play as and pure DD or buy warmoks instead of phantom dancers or madreds if there are no tanks in game or just a weak tank like and unfed shen or mundo that wont be able to do something intellegent..
then you arent as squishy as without :D
your bloodthirster should be fully stacked in every part in the game so try to play a little bit defensive if you arent dominating games at the moment what just can happen in the early game but if you practise a little bit it will work so good luck and have fun with my ashe build :)