Okay. I'll help. But I hate to do this since Miss Fortune is one of my favorites and it just bugs the heck out of me to have to face off against her. I mean how can you attack someone with hips like that? ...Ahem.
One shot, no kill. If you have decent health, Fortune isn't going to kill you with one attack. After the first hit, her attack damage drops considerably now. So, if you can close the gap to melee range, Fortune is going to have to hit another target before being able to hit you with a big damage attack. Stunned or slowed, Fortune is at a disadvantage. "But I can't get close," you might say. Charging in before mid game is going to be risky. But odds are that Fortune isn't going to have sufficient damage reduction before then to stand up to anyone.
Her R is scary. No doubt. But Fortune can't move or change the ability's direction once fired. Flash can get you out of it and leave Fortune in a very bad spot if you rush in on her at that point. It's also got a long cool down even with 45% cool down reduction. Once used, it's gone for a while. Barrier can save you from the first few volleys.
Unless you can quickly close the gap, don't chase Fortune. Even without boots, she's faster than you are. Don't tunnel vision.
Her Q is annoying but it has a limited target arc. If she moves towards you, back away or off to a side. She can't use it again immediately.
Even the internet shows say Fortune is overpowered right now. Oh, granted, she's got some great damage potential. But no matter how much health and armor you stack on her, she's a glass cannon. If you close the gap on Fortune, she's likely to fall quickly. But you're going to have to be patient, Leeroy. Let Fortune make the mistake and then charge in and destroy her.
(Sorry, Sarah. Really I am.)