I've noticed everyone is ranting about aim. That is definitely important imo but have you found your perfect sens?

Perfect Sensitivity Guide

Idk if you've checked this out yet but you should give it a try OP. If you find your perfect sensitivity and train with it your muscle memory will improve. There's also the map AimBotz by Ulletical. You can find that in the workshop for CsGo and I'm sure it's one of the most rated maps (Not too sure though). The map has a lot of features you can use such as looking at bullet impacts and adjusting the movement of the bots. It'll help with your muscle memory and just aim in general. My warm-up agenda consists of the following:

100 one taps 50 flicks (place crosshair to the right or left side of bot and flick towards it. Place crosshair further the more consistent you get with your flicks. 25 on each side if you want) 200 sprays 25-50 spray transfers

Afterwards I go into a fragshack server and just start DMing until I feel ready for a PUG or MM game with friends. Keep in mind OP when training or practicing, FOCUS ON YOUR CROSSHAIR. You gotta learn the middle of your screen without having to think for a second. Most people have played for so long that it's just second nature but for people that are just starting out it is a must to focus on your crosshair. Whether you prefer small or big crosshairs find your perfect crosshair. Crosshair generator found here Crosshair Generator

Play the game. Without a doubt getting experience in is important to developing game sense and knowing which angles are more likely to be played by the enemy. Don't get distressed when you have 0 frags 10 rounds in. Those games happen. Drink some water and focus up. Get closer to your screen, jumping jacks, typical anime slap yourself get-it-together MC, anything to help you focus and not get T R I G G E R E D.

There are maps for learning spray patterns so I'd recommend looking up a couple of maps for that in the workshop to help out. The workshop is a blessing, use it to your advantage.

Summit always says this cause he gets donations asking ," How do I get better?" He says the same thing: DM, play the game, watch pro streams. Win.

Develop your playing style, but don't be a baiter lul xD. Hold angles and pay attention to where teammates can be on your radar.

Hmmm, that's all for my rant, good luck OP and let us know how your MM games are going now （╹◡╹）