Hello, I'm zerker and I want to show you my guide to build succesful Ahri. 1st of all this champion is really hard to master. You have to practice long time.

Normal caster runes, nothing to say.

I think it's the best masteries for Ahri. Feel free to change it if you have problems with mana or anything else.

There are 2 ways to start:

Doran's ring

or

Boots of speed + 3x red potions.

Let's explain my decision about core items.

1.Rylais - some cc, nice ap and hp. This is really useful item for Ahri.
2.Sorcerers shoes - caster boots, you dont need ionians, trust me.
3.Deathcap - standard item for ap carry, you must have it.
4.Morello - great ap and cdr bonus. With blue potion and blue buff it gives you really amazing cdr. I love this item on Ahri.
5.WotA - works great with your passive and aoe skills. Also nice aura effect and ap, its cheap and awesome.
6.Zhonya/stepter - with rylais it gives really great survivability. Depend on enemy team you should choose one of this item.

This champion has really great potential. I will still work on this guide. I hope it was useful and helped you, enjoy and have fun with Ahri.