How do I reach gold as a support

I'm in Silver 2 (recently got depromoted from Silver 1 for the 3rd or 4th time) I'm a support main, I mostly play Sona. I play Soraka, Nami or Janna in cases where Sona gets taken or banned. I found myself a lot in teams where my adc goes in when he's low. My jungler ganks a winning lane or doesn't gank at all. And my teammates focuses tanks in teamfights and doesn't try to protect the backline. I really want to reach gold before the season ends. I've tried finding duos but I'm still losing my games. I would be happy if there's any tip that I can use to take myself to gold during this month.
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