Firstly, of course this advice won't work for anyone, but after being stuck in silver for months, following multiple youtube guides, I think I drastically improved my aim in a week and have moved up to gold, heading to plat. I was kinda shocked what worked and what didn't for me, and don't think youtube guides are too clear on players with poor-mediocre aiming, so here goes:

1. This is for players that can't hit headshots consistently enough or don't even try: go into unrated and aim alot slower. like REALLY take your time to hit a headshot, not to the body. This is harder as it seems as even in unrated I knew I could get a higher kd with aiming to the body so it was kinda of second nature. It's only unrated, ppl wont care about your kd just take your time. Eventually you will get faster and faster after a few hours of playing. Crosshair placement will come hand-in-hand for this, generally lower rank players that focus on crosshair placement is just too high.
2. Unbind right click: Seems crazy at first, but this was propably the biggest factor in my learning curve. Of course this means you can't use snipers for a while, and I don't mean unbind it forever, just a short time. The urge to ads was my biggest flaw, and makes it way harder to hit headshots, medium-close range. Even if you are getting demolished at the start from long ranges, getting used to your crosshair and the placement is vital and this can't really be done with ads.
3. Deathmatches: This has been said 1000 times by all good players, but I never quite understood just HOW important it really is. I played around an hour a day on deathmatches and although it can get very boring, it really is worth it.
4. Sitting arm-level with your desk: Also something I thought wasnt that significant. But making sure your arm is level with your desk and sitting up straight helps not just focus, and even a few inches can help with your arm movement.
5. Have light around your monitor: Generally I like sitting in the dark, but having light or any natural light around your monitor helped me. Can't really explain how but it strains your eyes less. This one was kind of suprising for me so idk if it's just placebo but worth a try.
6. Stop spraying with Vandal: The chances of a silver player being able to get a good spray through smokes with the insane horizontal recoil of the vandal is very low. Again, be patient and burst fire through smokes. Phantom is a better gun for spraying imo.
7. Change up your game: I use different enemy colours, different crosshairs each week to see which one I play best on. I think thicker crosshairs are easier to see for lower ranked players but thats my opinion. Most pro players say they look at the crosshair instead of the enemies so I guess crosshair means a fair amount. Changing enemy colours might help although it's really not that big of a deal.
8. If you're a duelist, don't think you're fine when you're top fragging, it means nothing and doesn't necessarily mean it's your teams fault. If you are frustrated that you're top fragging with reyna most comp games but still lose, try playing a Sentinel and see where you end up. Still top fragging? improve comms, try not to solo queue, and if you're team still isn't giving comms, tell them this and make sure YOU are trying your best to make an example for callouts.

If anyone has any other tips they found helpful please post below!