This guide is an introduction to support Ashe. It is not an in-depth guide. Main reason: I'm a little bit lazy and most people don't even read the text. Hope you enjoy.

I think people should ask why go with ADC Ashe. It is essential (IMO) for an ADC to have both an escape and some ability to boost your damage per second, and she lacks both.

On the other hand Ashe has:
Q: Powerful slow, no cooldown
W: Decent harass
E: Great utility
R: Deadly stun

Why do people even play ADC Ashe?

By the way, support Ashe is not a new idea. But it had not been played much lately and some people will even criticize you for picking her. One problem with this build was that it was too expensive to play. Season 4 gave support a lot of money so now this is playable.

Pros:

Fun to play
Unexpected to the enemy team
Permanent slow, no cooldown
Killer Ultimate
Nice damage early & late game

Cons:

Your team will complain about you picking an ADC
Squishy
Lacks an escape skill
Needs gold to be effective

Flash is mandatory. Ashe doesn't have a built-in escape other than Frost Arrow, and it won't work for that purpose in many cases.

The second spell is a free choice. I like exhaust because it's useful in early game. Loses it's utility later on.

Your main role in the laning phase is obvious: get kills, protect your carry, get them some CS, and so on. Use Frost Arrow to slow opponents and protect your carry, and also to try to kill the enemy carry.

After that, you will have to approach carefully from team fights/enemy team, fire Enchanted Crystal Arrow from a distance. Then start shooting slows and debuffs at the enemy team. Ascension is VERY useful specially with ECA, don't forget that.

Items are pretty much explained above, read the notes. The begginning is very simple. You have two choices when you get to the end of the game:

Awesome On-hit + Attack Speed Ashe: Deals great AOE damage and effects (note: you're NOT the carry but may make a difference with your damage)

Classic Aura support:

Other items:

Other than the items listed here, there are not many other options. Any items that give slow skills (Frozen Maul, Randuin's Omen, and others) are NOT good on Ashe because slows don't stack well (they are not additive and slows beyond the fisrt get a big nerf)

For now this guide is pretty short, but you can try it (just the items) and have some fun. I will improve it a little bit over time. Feel free to give feedback.