Hi, I'm ok at Yasuo, not some diamond Yasuo main or something like that. But I'm good at analysis, so here's my guide to Yasuo. This is WIP and I'm still learning to play Yasuo, so expect this guide to be updated. My first guide so chill with your criticism.

When you start, look who you're up against and who you're teamed with. If you see that you're against Ahri, you might want to start with some magic resist. If you have an aggressive jungle and a good synergy support, maybe play aggressive and go with Doran's blade. On you're first back you want to have about 1.6k gold, enough to buy Zeal and some boots.

Check who's fed and who isn't. This will help you decide whether to buy Ninja Tabi or Mercury Treads. It will also help you decide whether to go magic resist or armor. This point in the game is crucial to try to roam bot and get your adc ahead and get the first tower. You're top should be doing fine if they're a tank, but you might have to roam up there if they are a fighter. If you're top then try to roam mid a lot, get them ahead, you also might take Teleport with you if you want to roam bot lane. Whenever you can, help with the dragon and/or Herold.

Push your wave into their tower, don't just miss all the minions, so many people make this mistake. Make sure that your opponent is not in lane, don't just leave, let them get cs and then push into your tower, if you do that then you're dumb, sorry but get good. Use scuttle, dash to it, Q it twice so that you can get the knock up. You want to wait until the scuttle if closest to the lane you want to gank though, otherwise you'll run out of time to cast your Q.

Ward their jungle or else you might not have any way of escaping. Sure warding is useful because you can see where everyone is at, but it is also good for being able to see jungle monsters and then dashing over the wall. This is also a nice way to get your knock up ready, ward over raptor wall, dash and Q, Q again, dash over the wall again, destroy the opponent, win the lane. Very good for escaping if you are getting ganked.

You should have Phantom Dancer, Boots, and already have or be nearing your second/third item. Remember, dragon, inhibitors, towers, Herold/Baron, are all more important than kills. That doesn't mean give up an easy kill if you can get one, but don't waste 2-3 minutes on someone who doesn't even have a bounty at this point. Bounties matter, if you keep killing a Soraka who's 0/10, you won't get nearly as much gold as if you killed that one Tahm Kench, that's a flawless 42/0. Build against the strong opponents. If you have magic resist but their only magic character is 4/11, don't bother, stop building magic resist, most teams consist of mainly attack damage, so Dead Man's plate is always a good option, or Omen if you gotta go fast. Kill 2 people? Dragon. Kill the strong opponents? Baron. Never waste an opportunity to get an inhibitor, dragon, or Baron just because you have to back to get health. Those things are much more important than your life.

Spam your mastery emote and laugh on top of them. Tilting an opponent can actually win games/lanes sometimes.