You're probably in a similar position to where I was about 2-3 years ago so I am speaking from personal experience. Here a few things I did.
Critique your gameplay. Harshly if you have to. I did this mostly in battle, but the best players will often watch their own replays to figure out even the smallest mistakes. Look for the big stuff first. Where things went wrong. When you lost HP for no good reason. When and where you die. Look for consistent factors over multiple battles.
Never blame your teammates for consistent mistakes. You are the only constant factor over any significant number of battles. Accepting this now will help you grow as a player. Shitty teammates cost you games, but not enough to make a dent in your win8/winrate over thousands of battles.
Play for fun. I know this is pretty typical, but most players play worse when they are angry. Angry players tend to play more aggressively, take bigger risks, and generally make easily punishable mistakes. If you're mad at tanks, take a break.
Try 3 marking a tank. 3 Marking isn't just something unicums do. It is an excellent learning experience. 3 marking teaches you consistency so get out your favorite tank and push yourself in it.
Get out of your comfort zone. Kinda the opposite of above, play tanks you are not super comfortable in. If tier 9 or 10 isn't your thing, try it. You may find a tank you love and you will learn a lot by playing in tanks that push your limits.
Ammunition choices. Shoot ammunition that will work. If you see a superheavy, shoot gold at it. Don't waste your time trying to hit the hatch on top of a type 5 when you can press the 2 key and go right through the front. Glass TD asking for a paddling? Hit that sucker with HE and get some extra damage. Shooting the right shell at the right time will greatly improve your damage per game.
Learn armor models. some tanks have really easy to exploit weaknesses or complete BS armor schemes. Tanks.gg is a great resource to learn armor models and compare stats of tanks.
Finally be patient. It takes time to improve.
This is a lot of what I did. It took years to drag my stats out of the green and into the cyan/teal zone, but it isn't impossible. The first 10k battles I played I was a red shitter, but now I can play at a sub-unicum level with enough coffee or alcohol. If you're into watching livestreams, there are a couple of really good threads on good streamers to watch and @kolni (a washed out WoT god) recently started streaming.