Focus will allow you to land a guaranteed critical strike on your first shot of the game. Choose whether to use it on a champion or a minion. This shot in conjunction with Volley can provide substantial burst damage and give you the edge in a level one engagement.
If you are having mana problems then alternating Frost Shot so it only activates every 2nd attack might help conserve mana while constantly applying the slow.
Ashe'sFrost Shots apply the slow effect if the skill is active when the arrow hits. That means you can shoot an attack when the skill is not active, and toggle it while the arrow is midflight.
Keep in mind that champions with dash abilities can counter this tactic.
Volley has a fairly large cone and decent damage early/mid game. Use this to your advantage by positioning yourself to last hit minions and harass the enemy champions with it. Avoid spamming it early game as you most likely end up pushing the minions to the enemy tower.
Volley diminishes quickly in the late game; however, it still provides a great deal of utility. Volley can slow a great majority of the enemy team, can still be used between auto attacks, hit enemy chasing/retreating in bushes and it can pop Banshee's Veils.
Use Hawkshot to check the nearby jungle for enemies that may be attempting to gank you. It is also useful to check if the enemy is fighting the Dragon or Baron Nashor from a distance.
If your team is engaging either of those monsters, Hawkshot will give you advance notice of enemy approach, but also inform them of your general location.
You can use Enchanted Crystal Arrow to help your allies from another lane. If your allies have the advantage, shoot it further up their enemies' lane, and if not, aim further down your allies' lane. This may help your allies the opportunity to strike a killing blow or make a getaway.
Keep in mind that there is a low chance you'll hit them and you lose a lot of lane control if your opponent knows it's on cooldown.
Enchanted Crystal Arrow is one of the best initiators in the game, able to stun an enemy (preferably someone squishy) from a distance.
Enchanted Crystal Arrow is also a great skill for ganking. A well-aimed arrow can stun the target long enough for you or your jungler to apply their CC as well. Furthermore, Ashe's passive usually guarantees a critical hit if she has been traveling between lanes.
Enchanted Crystal Arrow is also a great skill when your opponents are losing the match and are running/escaping. Using it at the right moment can slow the whole team down, grabbing yourself an ace.
When shooting Enchanted Crystal Arrow towards another lane ping the area it will hit. This will alert your teammates that you have shot your ultimate.
Don't be afraid to use Enchanted Crystal Arrow to escape. However, be aware that the duration of the stun is based upon how far the arrow has traveled before impact.
Try to fire Enchanted Crystal Arrow in the same direction enemies are moving, so it is more likely to land a hit. It has a surprisingly large hitbox.
Enchanted Crystal Arrow is very powerful in Dominion, as the enemy champion's attempted capture would be interrupted while they are being stunned for 3.5 seconds and repeatedly shot at by the turret.
Ashe is one of the weakest 1v1 characters in the game when she decides to stand and fight. Assuming your opponent is equal to you in gold, Ashe is out damaged by nearly every other ranged AD character, quickly assassinated by nukers/bruisers if caught out of position, and heavily CC'd by tanks that she takes a long time to kill.
Her strength heavily relies on her ability to kite enemies and punish enemies out of position in team fights with her slow.
Stacking 2 Doran's Blades early game gives Ashe a much stronger lane presence, and are later sold for stronger items.
Ashe is a standard ranged carry and should be built accordingly. Rushing Infinity Edge is a very strong choice and generally considered the best way to build Ashe.
If your enemy is stacking armor, try to get a Last Whisper in your item build.
Statikk Shiv synergizes extremely well with Ashe because of Focus : As it can critically strike, staying out of combat long enough will transform the next auto-attack into an hybrid physical/magical burst.
Building Ashe as support is not ineffective as she does have a low damage output. Building auras and cooldown reduction is an extremely effective way to play her. With her perma-slow, cone slow, vision, global stun, and requirement to be in the back during a team fight, she can do just fine supporting her team.
Runaan's Hurricane lets Ashe apply Frost Shots on up to 3 targets. Even though, it is not recommended since Volley can apply a similar effect in a higher range and to a larger amount of targets.
Boots of Swiftness is highly recommended for three reasons, the difference in move speed is quite noticeable (and very much appreciated by such a "slow" champion), the unique effect of Boots of Swiftness is VERY useful (As slows are THE most common CC), and the minor Attack Speed bonus that Berserker's Greaves gives is relatively negligible, and better built elsewhere. Simply put, you get a lot more bang for your buck with Boots of Swiftness.
Ashe mainly deals damage by using auto-attacks, so buying Thornmail can help counter or even kill if she has low health.
Although Ashe is a great harasser during the laning phase, her low health is a great disadvantage. Putting pressure on her can keep her zoned.
Ashe is an unusual ADC, lacking any form of attack damage or attack speed steroid, however, Ashe strength relies in something that almost every other ADC lacks or has mediocrity: Utility, Enchanted Crystal Arrow alone packs a stun, something unique and very rare for ADCs, as well as having a sort of Frozen Mallet in Frost Shot .
Due to this Ashe's ability to gank or assist in a gank is the best for any ADC in game, watch out if paired with strong gankers such as Hecarim or Nautilus as they will simply CC lock you until you die.
Being tied for the lowest movement speed for champions in the game leaves Ashe vulnerable to skillshots.
Ashe has little to no defensive capabilities. Use this to your advantage. However, she can slow you constantly as long as she has mana, so wait before she is low before you go in to kill.
Gap-closers can quickly take advantage of this, since her slows cannot counter them.
Watch for when Ashe uses her Hawkshot. This tells what part of the map her team has no vision of.
At the same time, beware for the inverse. You might be tricked into thinking an area is un-warded because she just used her Hawkshot, while it was just used to lure you there after the effects wore off.
The most unique part of Ashe's kit is Enchanted Crystal Arrow , giving her a significant nuke and much appreciated hard CC (for an ADC this is extremely rare), simultaneously, she is quite dependent on her ultimate, so if you force her to burn it for an escape she is losing a large portion of her power and ganking abilities