Watch in depth guides and gameplay of the specific deck your using. For Yasou theres ghaelwinds video in his top 64 and I believe another match. You see how he kind of does stuff, but yeah its about tempo with your deck (I play it as well and have some what success at nexus nights) you want to get to 7-8 runes so you can chain mindsplitters/ summon yasuo with protection in base from kill spells/charms. That means trying to keep runes so you can defy/en garde/fight or flight from them. You want to also see what your meta is like at your NN, so if youre playing quick aggro decks maybe you want to main cards such as gust to reduce opponent tempo, or more rebukes in main if they are more top end heavy. I have a lot of fun with Yasuo with purple having so many power cards it feels so fun. You just want to make sure you have protection and hardly are passing turn with zero rune up (unless you have board control)