Anyone got advice on ahri?

be a bully early game because she sucks dick late game

I don't know what they are talking about just use your Q to damage your opponent in lane and if there aren't minions between you, also use E and W and this combo E-Q-W should deal around 50% of his hp. Save R to run away from ganks or to pick up kills, don't waste it. She is good in late game since she has a 2 seconds stun~pull, she cant be killed and they cant run away from her.

Don't you trust her?

2 words: Land charms.

As long as you land your charms you'll win.

A trick to land charm easier is to play weak, E when they chase after you or trying to skill shot you. They will have a hard time react.

Something nobody has mentioned yet is keybindings. (more specifically, smartcasting) If (during a game) you go into the menu and click on keybindings, you'll be able to change what keys perform what actions. More specifically, what keys are the "smart cast" keys. What is smart cast, you ask? Well, you know how Karthus' Q, Ez's archane shift, flash (and some other abilities), you need only use the key and it is automatically targeted at the cursor? That is smart cast. You can make any ability smart cast (though I've not tried with abilities like Rumble's Ultimate, Victor's death lazer, Varus' snipe, or other awkward ones). Having your abilities smart cast saves you fractions of a second for clicking, however, you will not see the "skillshot arrow" or the "aoe field". This can cause a lack of accuracy, so I only reccomend using smart cast (switching all of the smart cast keys to Q, W, E, and R) on appropriate champions (I never use it on Lux or Xerath, I use full smart cast on Evelynn and Ryze, and I use half smart cast for Nocturn). Ahri's combo (charm into ball) is a common smart cast scenario. I don't know if her dash requires a click, but I would certainly have that one be smart cast as well.

Hope my advice helpped.