I'M STRUGGLING TO GET BETTER AT THIS GAME

first step is showing your ranked gameplay

First, I would say that Nexus Blitz isn't a great gamemode to measure stuff by. It's faster, much more bursty, and has tons of crazy stuff going on that have a big impact on the game. Second, you're not even in focus throughout most of the video, so it's hard to evaluate your performance anyways. I'm by no means a great player, but I've been playing for a while and know a thing or two. Feel free to add me if you want, and we can play together a bit and see where you are at.

At a glance:

• You've a tendency to pop skills early, and then attempt to disengage immediately after.
• You need to work on gauging range.
• You need to work on using more than one skill per rotation... your E on Cait can be immediately followed by a Headshot - aka you can use it aggressively while still maintaining range.

Landing skills is only the first half the battle, you have to be able to follow up on them.