PSA: Learning to be carried is as important as carrying
Hear me out. I absolutely hate people who say "learn to get carried and just do what I say." That is not what I mean. However, I'm sure most people can think of a game where things just went wrong early, and you started to get frustrated w/ the game and down on yourself even though your team wasn't really behind. We also all know players who take on an attitude like "I'm behind and I'm the (adc/apc/riven top) so if I can't carry the game will be over," and the secret go going up in ranks is "you don't have to carry every game."
I recently climbed a second account from bronze to gold w/out a duo this time to see if I could do it (my mechanics are crap, but I make decent calls for objectives so w/ a duo who wins a lane consistently I can be all utility for them and win consistently), and as I got close to hitting gold again (my skill is low gold probably) I realized the biggest thing that helped my climb was not giving up or getting frustrated w/ games I was doing poorly in. It may not be a huge difference to win a couple games you would have lost, but when you save your promo from defeat because you won a game where you fed early, but mid/late game make the perfect cc pick, or body block as a mid laner to save the ADC who got fed (at the cost of your life) it is a huge difference.
PSA: Remember, even if you're behind you can still be useful to your team, even if you just serve as a distraction to make the enemy waste cc so that your team can clean up. You don't have to be the hero of the game in order to win, just be useful and land that clutch ult/ suicide block the jinx rocket/ whatever.