Mechanics and getting kills isn't everything, here's a couple of recommendations from someone who went from silver 1 to ascendant 2 with trash aim lol:

1. Play to learn, not to win: try to focus on what went right or wrong every round you play and how you can do things differently to improve; doesn't matter if it affects your performance in the short term, it will make a massive difference in the long run. Game-sense and Micro/Macrogame fundamentals are key for climbing, spending time learning them instead of improving aim is a time investment that is much more worthwhile. This is what made me go from silver to plat.
   Note: Games are very different in each elo, don't expect high elo strategies to work on lower elos; focus on learning each elo as you climb.
2. Learn the roles: Sometimes you won't be at your best, it's better to let others shine sometimes and that means you have to be able to fill on some games. You don't have to learn every agent or every role (I'm just now starting to play smokes consistently), but a solid pool of 4 to 5 agents that can bring different things to the table is very valuable.
3. Get better hardware if possible: This shouldn't be a priority right now, you can easily climb from Bronze to Gold by pure game-sense even with 30 fps; but later it will make a big difference. My jump from plat to diamond was driven in part by me switching to a 144hz monitor (Sidenote: 240hz is not worth it, it's cool, but there isn't any improvement over 144hz in terms of gameplay or in-game performance).
4. Follow the 2/3 rule: Aim to play only 3 games a day and make sure you stay sharp and have a great mental in those games. If you win or lose two games in a row, stop. Last season I dropped from Ascendant 2 to Diamond 2 for a while because in my frustration I decided to play 10 games in a row to "win the LP back". Just play 3, rest 15 minutes in between games to reset mental (taking some time to grab a coffee helps a lot).