I am in plat right now playing mostly top and support. And if I knew what supports you play best it would help but in solo queue especially in low elo, where nothing is warded, its best to take supports that can roam to mid or top fast with good cc or damage with mobility boots because even if you lose bot you can still get top or mid fed. Usually its easier to roam mid tho. I play janna a lot because she has 3 cc abilities and her shield can give damage and help someone live but nautilus, blitz, thresh, and alistar just to name a few are pretty good at roaming too.
Another thing you can try is just getting good at aggressive supports like blitz, thresh, annie, and morg and just get your adc fed enough to carry then all you have to do is protect him to win. Or you could play zyra, morg, karma, or leblanc and try to carry by building offensive items and basically be a second apc but only do this if your good at one of them.