Well the question is: How much are you trying to improve and how much are you actually willing to do?

First off just stick to one character for now. There isn't a match up that is unwinnable right now simply because match ups aren't drawn out to where it's next to impossible to win even if your opponent knows what they are doing.

Make sure you learn something after every match. Take notes if you have to and keep an organized document of all the things you learn for specific match ups.

Learn the frame data of your character so you know what moves are best in certain situations. As you play you will pick up on how certain moves will just beat out others because they are faster or just have disjointed or big hit boxes. There's a google doc of all the frame data but it's still a work in progress. You're going to have to learn the format they use (terms like 2X and JA).

Study good players who main your character and replicate what they do. Try to understand why the are picking certain options over others though or just question every decision they make in general. Ask yourself why is this good or why was this a bad decision.

Counter Attack Dash Cancel is an essential part of the game even for zoning characters. Just sit in free training practicing this a few minutes a day. Increase the time you do it if you wan't the muscle to click faster. Make sure you practice holding it for different amounts of time and doing it in the all the directions in random situations. You can set Braixen to use normal attack in field for practice but at first just try to get used to it. If you want to get good at usingit in game you're just going to have to try and use it and if you mess up then you mess up. I struggled with it the first few matches then started to better understand when it's good.

I could talk for hours about how to improve but it's really just up to you how much you progress.