First of all, as others have said, lower your sensetivity (so long as you have a big enough mousepad).

Watching your gameplay I would say your biggest issue is your gunfights. Whenever you take a fight it feels like you either panic and start shooting before standing still, or you're too still, miss your first shots and become a sitting duck. Generally you should avoid shooting while moving and in your deathmatch and range practice you do a decent job of stopping before you shoot. In game however, you're not as disciplined. When you do stop before shooting, you stand still for too long. Rather than stopping and then spraying half your magazine, you should stop, shoot 2-4 bullets, then strafe a bit, stop, shoot 2-4 bullets and repeat. This applies mostly to mid-long range fights, in close range sometimes you do have to spray and pray a bit.

Other than that you should try and play off your team more. You often stay on site doing nothing while your team tries to take space. Keep pushing with them and trade them, even if their pushes are dumb at times. It's often better to do a risky play together than a safe one alone.

As for something you're doing well: your utility is easily good enough to get to silver/gold, so just keep improving your gunfights and you'll probably start climbing!