You are extremely strong during the laning phase due to your long-ranged poke and auto-attacks. This allows you to play safely, chip on your enemy's health bar, and then all-in them with your Q empowered auto-attacks.
The amount of utility you bring to a team comp is massive. Your auto-attack slows and your Ultimate R CC can easily help your team secure picks before important objective fights. It also helps you increase CC chains on enemies.
Once you get two to three items, you can start slowing and shredding multiple members of the enemy team in close-quarter fights. This gives you a greater time to kite out enemies during skirmishes and keeps you safe from their CC while your team piles on them.
Your immobility is the clearest weakness that you have, both during the laning phase as well as the team fighting stage. This puts the additional task of making sure that you are positioned well during fights as one misstep can get you killed.
The enemy team will look to gank you multiple times during the laning phase to set you back. Although it doesn't affect your utility, you won't be able to get enough items to impact fights later on which will cost your team multiple fights and objectives.
Farming alone in the side lanes can be really dangerous for you as you are quite easy to get picks on. You only have your Ultimate R to protect you from the enemy. Any form of CC is a weakness for you during the entirety of the game and you may need to rely on your frontline to keep you safe as you have no dashes in your kit.
0 - 15 min
Your initial plan will be to play the lane safely and not get cheesed early on by the enemy Jungler. Set proper vision around the lane and use your E to scout your surrounding before you decide to push the wave.
Maintain your range from the enemy and keep poking them whenever an opportunity arises. The best thing to do will be to use your W in such a way that it hits both the enemy champions and the minions at the same time. It will give you push priority as well as the trade advantage.
Try to save an E charge for when you skirmish with the enemy bot lane. This will prevent the enemy ADC from dropping vision in the lane brushes. Also, always keep your Q charged up as you don't know when it can come in handy.
15 - 25 min
Due to your range advantage, you should always try to push the wave in when the enemy Jungler is not near your lane. This will allow you to whittle the enemy tower down and possibly take it quickly. Once that is done, immediately swap to the mid-lane as you will be safer there and will be able to get more objectives that way.
Before major objective fights, use your E to scout around for death brushes set up by the enemy. Besides that, always maintain your range and use your Q and auto-attack slow to constantly kite the enemy team. You don't want to get caught out by any form of CC as it will spell death for you then and there.
If the enemy carry is highly mobile, you may want to save your Ultimate R until you have a clean shot on them. Getting them CC'd will allow your team to collapse on the said carry while giving you enough time to position well.
Provided you didn't fall behind during the early game, you should be a powerhouse of damage and slows during this phase of the game. You should use your range advantage and always go for front to back trades when fighting the enemy. Always look to auto-attack the enemy champion closest to you (while trying to W multiple enemies) so that you can kite them long enough to get out of their influence area.
Your Ultimate R can be a game decider if you use it properly during this phase of the game. Use it in combination with your W to secure long-ranged picks for your team. During objective fights, you can use the same Ultimate R to CC the enemy Jungler, so that your Jungler can Smite the objective safely.
Try to obtain mid priority with your team before you take any kind of objective. You don't want to be in the side lanes unless it is completely pushed into your tower else you will get caught out easily and will get killed immediately. Also, don't forget to buy some form of anti-CC if the enemy team has a lot of champions with hard CC abilities on their side.
At level 6, Ashe’s kill pressure in the lane increases. Her Ultimate R is very versatile and can set up kills with her team. Make sure you play around your Ultimate R to get kills over and over.
Once Ashe has a few points in her W, her poke can be incredibly challenging to deal with. Make sure you harass the enemy as often as you can
After your first back, you will pick up your first component item. The extra damage it provides will help you in extended trades with your Q, and increase your poke damage with your W. Start playing more aggressive after your first back.
At level 9, Ashe will have her W maxed. This is an important power spike for Ashe as she can use it to poke the enemy down before her team commits to a team fight.
When Ashe hits level 11, she will put a secondary point in her Ultimate R. Her Ultimate R will have a short cooldown and she will be able to look for picks frequently throughout the mid-game.
Ashe should’ve completed an item or two during the mid-game. This makes her a huge threat in team fights as her damage output in conjunction with her poke can be devastating to deal with.
In the late game, Ashe’s W will be on an incredibly low cooldown which allows her to poke the enemy down a ton before a late game team fight erupts.
At level 16, Ashe will have 3 points in her Ultimate R. It will also be on a much lower cooldown (on a lower cooldown than the enemy will think). This allows her to get surprising picks to win the late game for her team.
In the later parts of the game, Ashe will be at max or near max build. Her damage output will be incredibly high if she can 1, poke the enemy with her W, 2 activate her Q and 3, kite in late game team fights.