I feel alot of the trick to ranked is knowing when and how to push to win at the moment. When you can't win team fights, split push like hell and base race if you have to, sometimes however you just gotta fight, and you always want to fight in the best advantages possible for your team.
Also, I suggest you troll some normal drafts to feel better and if you lose a ranked game take a break and do some normals til you feel more confident.
If you feel you can not win a game, and there is no point in continuing the match, press onward. cause if you surrender , and don't see how it plays out or at least force them to pay hard for every objective taken, you will not improve. Learning to master aggression and have map control is important.
ALso, learn how to best fit your team's composition, and counter your enemies. if they have all high burst champions, get cc and healing, if they have high cc and healing get sustained damage and tank.
Simple example, enemy chooses blitzcrank: sivir, ezreal, leona, and nidalee all provide best counter play if you can time your skills. Enemy chooses Teemo: Elise, kenen, vlad, and mordekaiser are all good counter picks. Enemy chooses katarina: Dodge que ban katarina(jk: malzahar, pantheon, brand, argueably TF, and Cho'gath all do wonders to kill her, or elise.) Enemy Chooses Akali: Diana, leesin, Evelyn, and I would argue for Mordekaiser here as well.
Every champion can be counter played as well: Vlad, malzahar, ww, rammus, and morde are all vulnerable to QSS, Champions with execution moves like Darius, garen, lux, Riven, or Cho, get a hex drinker and a red pot to pop at the last second to stay your execution if you can time it right. Also: If they have a jungler, WARD YOUR ****, and pay attention to the mini-map. For refference I give you the map awareness song:The Mapawareness Song
This all said, Ranked=Effort, if you want to be in the highest ranks, you gotta work for that **** and know what the hell you are doing, cause odds are, someone on the other team wants it just as bad as you and will do everything they can to climb that ladder. This is why i stopped playing ranked, cause i like to troll every now and then, and Ranked is not the place for that unless you duo que or are pub stomping **** with premade 5's.