First thing first is to always focus on yourself. It's hard, but there are probably some things you are doing wrong. If you die, blame yourself, not your team. If they die, you probably could've done something to help, even if all you did was ping Danger or ping Assist me. Most of us need to learn to CS better, or to look at the mini map more, or need to understand minion wave management more, or to focus on objectives over kills, along with a ton of other things. Make sure you are doing things the best you can first, because that alone will help you climb out of Bronze. You might not be punishing your enemies mistakes, which means you don't get the kills your need to carry the game. Yeah, your team might be feeding, but it is possible to carry feeders if you play well. If you don't think you can carry, that's fine, but don't blame your teammates cause that won't help you improve.
Accept some games as losses and don't let them phase you. I played a game as Morgana support on a different account, teammates dying left and right to picks. I think I built Morello and then support items. I had the most damage on my team. When your teammates are a Syndra, Jinx, Kha (can't remember last teammate), it's really sad when the support beats them. If your team is dying a lot, assume it's probably a loss and just do your best. Keep trying, but don't get upset by people making dumb plays. I had a game where my ADC could've been a beginner bot and they would've done more that my ADC that game. Luckily the rest of my team carried, but I stopped trying to make plays around my ADC when I realized that my ADC wasn't going to follow up on my plays.
Maybe play an early game champion so you have a power spike earlier. No one wants to wait 40 minutes for you to power up. You might be a god Anivia/Cass/Kass/Ryze/GP/Vayne, but when the score is 0-30, no one is going to wait hoping you'll hit your power spike and carry them. People also don't want to be carried, they want to do the carrying 90% of the time, so waiting for a teammates spike never crosses their mind cause they'd rather just forfeit and play another. If you have early power, you might be able to win lane, thus transferring your lead to help these losing lanes. People are sometimes willing to play a 40 minute game if they have a 5/0/0 top laner saying just to scale vs a 0/0/5 top laner.
Ping your teammates if you can. Try to help your teammates make good decision. ADC is solo splitpushing bot lane and the rest of your team is top, ping Danger near your ADC. You just got ganked by the jungler in top lane and your jungler is in bot jungle. Type "Jungle top side" and maybe danger ping the brush on top side mid. Maybe ping the dragon if your jungler can solo it or ping bot side hoping your jungler will gank bot knowing he can't be counter ganked there. Or maybe ping the enemy jungle to see if he can steal some camps from the enemy. If you push the wave into the tower and know that it will bounce back and push to you in a minute or two, type "top lane pushing to me, easy gank in 1 min." You see the enemy jungler and ADC bot side, while your team is near mid. Spam ping Baron and say, "jungle ADC bot, rush." Now, your teammates might not listen to your plays, but sometimes they will and if you can make a good call at the right time, that might be the game changer.
Same as above, ping your team, this goes doubly for if you are dead. When you are dead, that means you can't do damage to the enemy, so you have nothing else to focus on but what's going on. Did enemy ADC flash? Ping it. Did someone TP? Ping it. Did you get an Ace and see someone recalling or going for Baron instead of getting the open inhib, ping it. Is your team trying to kill an inhib and the enemy is respawning soon, ping it. Sure, you can take that 30 second death timer to go run refill your drink or eat your pizza, but why not try to help your team instead of being literally dead weight?
Talk in vague terms if you want to say something to someone specifically. Say "we need to group" instead of "Jhin, just group." Say "Buy armor, they're mostly AD" if someone is dying to AD damage instead of "Syndra, stop rushing Morello and get Zhonya's."
From my experience in Bronze, it's mostly about punishing your enemies mistakes. I mostly play support, so when I think I can get a good trade on the enemy ADC in lane, I go for it. If the ADC is alone, I will blow my flash for an attempt to kill them, cause even if they flash to avoid it, that means I blew a cooldown that might've save them next time. Don't use things randomly. Have a plan for when you use your abilities. So many people use stuff randomly. If Blitzcrank misses hook, for example, he is basically useless for the next 10 seconds, so you can tell a difference between a skilled player vs a newer player cause skilled players will hold certain abilities just for the fear value they have over actually using said ability. For GP, for example, use your barrels to zone the enemy from CS. You can stand in your barrels and CS freely while possibly zoning them from CS, which means you'll get gold quicker and be able to get items quicker. If they step well into your barrel, then blow, not if they are just skirting around the edge of the barrel range. GP has a free cleanse, so know if your laners/jungle has something you absolutely need to save that for or if you can use it simply for the heal. Understand how to trade and look up how to do it properly. From what I remember (may be completely wrong) but it's something like: wait for your passive to come up, Q into barrel combo, if it hits, run in, auto, barrel if available, auto, Q enemy as they walk away or Q barrel for more damage/movement speed. I see people do this a lot where they have a long range ability (like Caitlyn ultimate), that they use while the enemy is in their face instead of using it once the enemy is outside of their auto attack range or their short range abilities.
Some of these guys can carry but they can get the job done at top lane and carry your teammates.
