Learn to play to your play style. SO many people I see jumping on the advice of "play x bc it lets you do y and that is how you carry yourself." While that may be true, people have an easier time being willing to invest the energy needed to learn and improve w/ something they enjoy and have fun w/. One of my absolute favorite streamers is this guy called soultran, who plays tank sion mid at the diamond level. If you ask what to carry w/ no one will ever say "main sion mid and build him tank," but the dude loves sion and he's really good at it. The trick is he learned to roam really well w/ sion and he gets his whole team ahead pretty consistently from playing mid and ganking side lanes a ton (often diving bc he's a fat ass tank).
Figure out what you love and just try to get better at something specific each game. I love nunu and focusing on dragon control taught me to do that so I got better, learning to peel better and adjust item builds as needed boosted my nunu another level, learning when to max q vs e, and often mixing them (2-3 levels in q for early dragons and then leveling e to gank more) improved my play again. When I played heimer for objective control I improved my harass, then improved my tower dive w/ ult q at level six, then my roaming/dragon control. You can carry from any position and w/ any play style (tank, sustained dps, burst, whatever) if you get good enough at it.
Lastly, try duo queing. Play w/ someone who complements your style. Do you destroy lane but can't finish games? Play w/ someone who makes good objective calls but is too weak mechanically to do better than go even in lane. Do you judge baron damage and how fast you can do it better than your teammates? Are you always the guy pinging where the enemy is coming from even when you don't have vision bc you just know what the right play is and you've figure out their patterns this game? Get someone who is great mechanically and let them crush lane so you can work together for objectives and get the whole team ahead. GL and have a great time climbing.