I can win in theory against any Champ in theory except Zed. I dont know what to do against him. He dominates the lane early and the snowballs into the late game. I havent one once against him when i was mid the only times ive won was when i was a fulltank so what should I do when im playing a regular midlaner
You don't. He's designed to win or go even mid lane. You need to focus not dying and calling MIAs so as not to let him feed. He falls off the longer the game goes since he's not too effective in organized team fighting late game.
Bait his W, get a zhonyas, being exhaust, etc. stay back and farm, don't try and constantly fight him. He will out sustain you resource wise.
If you can trade or do damage though, don't hesitate to as long as you don't have a chance of getting destroyed yourself. Zed power spikes hard at 6, but if when he hits 6 he has little health, you waste a lot of game time since he's supposed to get a kill at 6 and now he will have to back before he can kill you.
Also counterpicks. Malzahar, Lissandra, etc.
Well... when his shadow clone is down, you can easily harass him knowing that he can't gap close on you, or get that extra damage from his shadow clones when he ults you. So why not abuse that? Also try to read his movements. Is he going in for poke with his shadow clone? Maybe side step it before he uses it.
Yeah i consider Zed like a midlane Darius/Illaoi. You don't need to kill them to win lane, all you have to do is avoid giving them kills. They don't scale unless they've got a few kills lead.
Of course it can't be helped when they ignore all your pings and stay pushed when Zed is mia only to give him a juicy double kill. I cry inside when my Zed goes 8/0 and i didn't die once to him.
If you dodge 9/10 of his Q's, bait his shadow, and punish him when he tries to cs; you stand a good chance at going even.
It really all depends on your champ. I play mostly 
. So i make sure to hit him with Q everytime he steps in range, dodge his q's, and AA trade when his E is down. If he ever uses shadow to farm or poke, i can E on him for free and combo. I try to get a feel for him in the first few levels. If he's skilled, i rush 
. If he's average/bad i just rush my usual 
and get second/third.
It's really all about whatever champion you main and how their matchup with zed plays out. Some people can go aggressive and outplay, others can only play safe and hope to outscale.
