Fyi, last whisper is absolutely core on yasuo. Once you get LW you can break the game wide open.
Why? Yasuo already has the damage to shred the squishies, you don't need 6 bloodthirsters to do the job. Last whisper helps yasuo's midgame tremendously. Also, you gotta work on not dying less, yasuo baits people to press r every time someone is knocked up and it isn't always the best idea. Also, try not to use his e so aggressively. If you e in and can't e out, you're stuck. Yasuo needs knowledge of where the jungler is in order to be aggressive.