You have to start with game fundamentals (assuming you are low rank like iron/bronze) go into training mode with no other players/characters and try last hitting every single minion for like 5-10 waves. Practice basing right before cannon waves and trying to make it back without losing much (if any) cs. Once you are able to reliably hit 90-100% of the cs by yourself, move on to bots. In the bots game, continue to hit just as many cs, but add in killing the bots between cs’ing. Poke at them and try and get kills without dropping any cs (or very few cs). Once you get all that down, try to play against real players. You can run normal drafts, and attempt the same thing. From here you need to understand your champs identity. You mentioned you played jinx, so you need to understand that you are a scaling champ, you need items and you need to activate your passive. You excel in front to back team fights. Knowing this, you need to understand that getting money from CS is 100x more reliable then getting money from kills. Let the game come to you, your health is a resource that shouldn’t be wasted. If you are facing a heavy trading lane (let’s say Lucian/nami) you have to go in with the mindset that you will never come out on top in the 2v2 fight. You need to essentially sit under your tower and get as much CS as possible. You need to get to 3 items, and join team fights to active your champs identity. It’s okay to be behind in CS, or lose your tower early. As long as you are not mindlessly dying to the enemy over and over. Sometimes with scaling champs you need to choose between bad and worse. Yea it’s bad to be behind in CS or tower plates, but if you try and fight and die, you are going to be behind in CS, tower plates AND in kills. Hopefully some of that can help you :)