As my title suggests, this Ahri build is taken directly from my personal Lux build with a few tweaks. It is meant to encourage spammage of skills and and burn mana.
This build will have two ways in which I will discuss.
Way 1 is simply survival to stall and annihilate your enemies.
Way 2 is to spam burst and kill as quick as possible and then run away, basically hit and run.

Also NOTE:
This is the first build I have released on Mobafire, all friendly criticism is accepted. I'll enjoy any feedback on if this works for you.

I go with an 8-0-28 Mastery build
I get only a bit of AP and CDR on the Offense side to get my Ghost higher speed. I dump everything else on the utility side for the extra CDR and starting gold as well lower CD for Flash.

Normally I would stick with Ghost and Flash. These 2 spells will save you correctly time and time again. For one, Ghost will help you catch up or run away after you have used your ult. Flash can help you get an extra kill or ace as well as save you. But I'm pretty sure all you experienced players know this.

Items
1.Boots of Mobility + 2 MP + 1 HP pot > Sorcerer Shoes or Ionian Boots
This is your starting build, I only encourage this start if you are fully aware of the map and extremely cautious in placing your self. Otherwise start with a Doran's Ring. You will later upgrade these into Sorcerer for that extra Mag Pen, or go for epic spam with Ionian boots.
2.Rod of Ages or Archangels
This part is up to you, it depends on the other team's status. If you notice the other team is starting to get a slight advantage, go for the RoA to improve your survival. If you notice your team has a good advantage go for more damage and a longer mana pool with Archangels.
3.Rylais Scepter or Morello's Evil Tome
If you chose Rod of Ages and Sorcerer shoes, start focusing on building a Rylais, this will not only get you more survivability but also more ability to catch and stay with your target. On the other hand if you chose Ionian boots, and Archangels, go for Morello's which will improve your CDR to nearly 40% or actually 40% if u have masteries.
4. Rabadons
This item is a must item once you have gotten your first three. By the time you get this item, it's probably your side is nearly winning or its just a long drawn out game.
5. Zhonya Hourglass
If you somehow managed to survive up until this point, I'm pretty sure the game is getting near the end. This is for surviving those pesky ults like Karthus or Nunu's.
6. Archangels or Guardian Angel
By this point, you should be either having a situation where an Ace means GG. So to prevent this ACE, get an Guardian Angel, or if you feel very confident, get an Archangels to ACE them instead.

I start off with 1 point in Q for basic harassment and minion farming.
I put the next point directly into Charm for the basic combo of Charm > Orb of Deception (OoD)
After that I'll put one point into Fox Fire, if you ask why I put 1 in fox fire at level 3 already, it's because of Ahri's passive, it requires 9 hits of your spells. Q hits up 3 charges, W, hits 3 guaranteed charges, and E only hits 1. Q costs the most mana in the beginning so its only good for getting life from minion waves once you charged. You will want to mainly use your W to get 3 charges for you passive. That is why you should max out Q and E first and then put everything else in Fox Fire afterwards. Also E and Q will be main combo throughout, W will just be your backup just in case they're low on health and you are chasing them. One more thing, Your Charm should be maxed out really soon, possibly even before Orb of Deception if you must because that will save you if used correctly. And always of course, get your Ultimates at the usual levels of 6, 11, and 16. It's surely going to help you a lot.

Team Work is COMPLETELY ESSENTIAL.
You cannot go One Woman Army unless you are fed by a margin of 10 kills.
Otherwise, STICK with your team mates. You will most likely be the best target for the enemy team to eliminate in a flash. Many champs such as Tryndamere, Fizz, and Veigar will exceptionally mob you if you aren't too careful and will end up costing you the game. Remember to coordinate and if you can communicate with them via Skype or just chat and try not to make costly mistakes that could like for an example reveal a gank or back door.
If your team is completely neglecting you or criticizing you harshly, try to point out reason you might be having a negative score, unless you yourself clearly are the one feeding in the first place, all I can say is "it happens". If your team is doing well, keep encouraging, and work well together to win a fast and easy game.

Pros

• Good survivability
• Good spamming
• Fun harassment
• Carry if played correctly
• That's all I can think for now, I'll update this with any comments.

Cons

• You're gonna need practice
• This follows one rule similar to TF, you either do good or you feed
• You will probably get focused
• That's all I can think for now, I'll update this with any comments.

Ok now for an important section.
You MUST be very skilled in last hitting or else it will be a hard time getting all that gold for this build to be effective. For those that don't know, LAST HITTING is technically what the name implies, you WAIT till the enemy minion gets to low health and then deal the killing blow for the gold. IF you ask how the enemy minion gets to low health, its called your own minions. Aside from this farming should be fairly similar to all ranged AP characters like Lux or Veigar.