Know what you mean, I've been working to climb out of bronze with my friend, for the most part we win consistently, but there are always those few games we lose. Normally the best thing to do is take a break after every ranked game you play, around at least 20 minutes minimum, you could use that time to find mistakes in your past games and capitalize on fixing them in later games. I think its not only important to counter your opponents champions, but you also need a support that makes up for whatever your adc is lacking. Such as
, while cait has really good critical hit scales, she lacks escape and mobility, therefore you need a disengage or something that will negate the opponents engage and turn the tides in your favor, personally I don't play
, but he has a really good engage and disengage using his R, as well as his shield which reduces damage, this champ works well with those squishy back line champs. Playing as a support its important you choose a support that benefits the team, if your team lacks engage pick a support that has good engage, or maybe your team has a strong back line that can deal out a lot of damage, and thats great, but if you have no tanks your back line is sitting ducks.
You can feel free to check my match history, but I don't know if its set to public or if thats even a thing. If its not public, I'll tell you I mainly support Blitz and Thresh, since both can pick off the back line. If the other team makes a mistake, capitalize on it and do whatever you can to punish them as long as its a worthy trade. Its also a good idea to use bans to your advantage. This info is very in general since I haven't gone ahead and looked at your match history, I'm happy to give you any advice I can if you need help thought.