heres what i did. i found a couple champs and i play them all the time. my two main champs are ap teemo top, and mordekaiser top. i have figured out builds that work for me with both champs, and i understand how to lane with both champs. i off play karthus mid, but i am still learning him so i dont play him as often.
i have learned how to communicate with my team, instead of telling them what to do, tell them to be patient, and dont jump right into things. tell them to poke instead of going in full blast (these things work).
i dont really support anymore because last season i mostly mained soraka support because i was new in ranked, and i still managed a 24-16 win/loss record with her, my best champs last year were mordekaiser, graves, master yi jungle, and soraka.
this year my primary problem is laneing vs miss fortune because of her double shot, so i plan on buying her and learning what makes her so good as an adc, in how shes able to push a lane all the way, and play very aggressive with any support. this year however, im like 3-2 or something with graves as an adc, for whatever reason im not that great bot lane this time around, so i changed lanes, and learned another champ, (ap teemo). also for whatever reason, this time around im not able to play master yi very well, not sure why.
champs im bad with are:
so i refrain from playing these champs more then 2 games, however, i dont play them at all anymore because i am just not that great with them period.
my point is, OP, learn from your mistakes.