Ayo! This is my first guide. I did everything to keep it short and simple, bacause I'm sure most of people are not gonna go through walls of texts (judging by the way I am) and are only browsing a champion guide to quick check on Items, Runes, Masteries, Skill order and Combos.

Ahri is one of the champions in LoL there are not built like the tipical Annie, Tristana, Shen, Irelia and Soraka.And thats why I decided to make a guide. Hope you find it helpfull :)
P.S. sorry for all the grammar mistakes and terrible english :(

Greater Mark of Magic Penetration - Magic pen is the best option here.

Greater Seal of Scaling Mana Regeneration - To be honest I hate these seals, I only use them on Corki but it's a must for this build. Together with Doran's Ring they will make your skills pretty spammable and you need start charging Tear of the Goddess as soon as possible.

Greater Glyph of Scaling Ability Power - My personas choice. You can also use flat ap Glyphs Greater Glyph of Ability Power for better early game.

Greater Quintessence of Ability Power - Personal choice. You can use Greater Quintessence of Magic Penetration also a good option.

> > >

Core

After you're dont with the core you can go for Deathcap, RoA, Frozen Heart or Banshees.

Go for Deathcap if you're doin well.
Go for RoA if youre not sure what's gonna be the outcome of the next team fight.
Go Defensive If somebody in the enemy team is fed Frozen Heart -anti AD, Banshees -anti AP

Harass -

1 vs 1 - This might sound weird but in 1 vs 1 try starting with your ultimate the whole combo should look like this Auto attack Auto attack Auto attack

Team fights - In a team fight pick off a dangerous carry/squishy with your combo try to do some auto attacks in between the spell casts and leave youre ultimate for the end.

Remember auto attackin after a spell cast does "tons of damage" with Lich bane proc.

Pros Lots of utility True damage Long range Taunt Is a sexy fox

SPACE

SPACE

Cons Squishy