Ultimately it's all about attitude and comfort. Yes, bad games happen. I feel like I've had more trolls, leavers, and feeders on my team than the enemy team by a huge margin. But that's also because I probably remember those experience more than when I got to walk down midlane at 15 minutes for a free win.
One of the most important things to remember is that ranked is, at least when I played most often, a collection of misfits that are trying to play a game together. For better or for worse you can't just ignore them or let them run around doing their own thing. Take charge early and forcefully, actively praise good plays more than just a "Nice" and don't let misplays become a focus. Let them slide, say it's no big deal, be a leader and shot caller. Sky Williams actually made a video about this tactic and it really does work it's kind of amusing. As a support you're in the best position to do that. This is by far the most important thing you can do, especially in silver/bronze. Warding up and timing buffs doesn't do much if your team doesn't even look at their minimap. You have to force-feed your team this knowledge and the only way to do that is being the leader.
Supports also dictate botlane. ADCs are the stars of the lane but a good support can easily forcefeed his carry 6 kills and mountains of farm. I've had Sona as one of my main support for years (who would have guessed lol) and more often than not I play her like she is a murderbot. I never go passive, I'm always dictating the pace of the match even if it means some games I end up overstepping and getting killed. By doing this I force the enemy team to earn their farm and a lot of times it results in me first backing into a sheen and straight up dueling the enemy ADC while the enemy support can't match me because he went back into a sightstone and upgraded gold item. You have to be very aware of your own damage because it's the only damage you can rely on.
That being said, don't get caught up in damage supports. As much as going bot as a murder lane with Brand or Annie feels like the best way to climb I've never felt they were as strong of bullies as Sona or Soraka. Yes, I play Soraka as a bully, it's absolutely hilarious.
Either way, don't play "Meta picks" just because they're meta. Play your favorites, play what's strongest for your playstyle. I've stuck to my guns as a Nautilus player through thick and thin and despite, at times, being one of the worst junglers in the game or not even considered a jungler by the community. I've maintained a 65%+ winrate over like 150 ranked matches on him. Do remember that there are diamond 1 tricks for about every champion. It always feels great to surprise people with just how crazy the plays can be when you're playing with someone that's got like 500 hours on a character. Can't tell you how many needles I've managed to thread with Nautilus' hook.
As a wise fighting game player once said, "Pick yo shit!" I think it applies well to this game as well. Hope this helped!
