This is all just from my experience I climbed out of bronze3 and into gold 5 season5 and silver3 to plat5 this season
It don't matter if you get a S / S+ you are still going to lose the same amount of LP.
Champion Pool: You wanna pick a high burst support (like Annie & Brand) or a very aggressive tank (like Leona & Thresh) back when I was in low elo I learned that it was better to just snowball like crazy rather then try and play for teamfights / late game therefore a champion like Janna is not that good(in low elo she is still a great champion however).
Laning Phase: Try and poke your enemy out of lane, a good way to poke is every time they go up to last hit a mage minion just auto attack them, they then have to make the choice of getting 20gold and losing the trade or auto attacking you(even trade pre lvl6) and miss the 20gold, and then run back into your bush so the minions lose vision of you and stop attacking you (just run back if the bush is warded) and if you are running thunderlords its great to auto, ability and then auto for a great chunk of their HP. If they are real low tell your adc to stop pushing the wave and freeze close to your tower. And then stand in front of their minions and just zone them from getting the cs, this is a great idea pre recall because they wont get the gold they need to match you first back. Once you do get back you have much better items and you need to abuse that(poking hard) and depending on the situation you can just constantly shove and try and get the tower. Make sure you always have a pink ward down and tell your adc to get one too.
Mid/Late Game: After you get bot lane tower see if you can rotate mid and get tower, and if you cant look at top lane and see if you can get that. make sure your adc is following you(if your adc is fed enough to 2v1 then feel free to just constantly roam and go for objectives just keep a eye on the map), and just keep rotating through towers and apply pressure to every lane. And if you are working on inhib / inner towers make sure you are always trying to steal the enemy junglers farm, and always be ready for when dragon comes up. Make sure you are constantly warding all over the place.
Team Fights: If your adc is doing great then just stay on top of him and peel hard core for him and if his not just try and jump on the back lines(if you are a bursty support that is) and once you take out one of their carries jump back on your adc and peel the tanks if he is still alive if hes not then just keep going hard on backline. however do not do this if they have a really good peel team comp / tanky. if you are playing a tank support however try and get a good engage and then just peel for your adc. This is just a really rough outline on playing team fights and most of it is situational so you will need to make your own judgment.
Final Tips: Realize you cant win them all, there are some games where you just cant win so don't beat yourself up over it. Climbing in ranked is a process and it takes time, so make sure you don't get tilted after every loss. Take breaks and don't play while you are tired (you play alot worse then you think trust me)
This game is ALL about situational stuff and you will learn more and more as time goes on however I hope you learned something from my rough idea on how a ideal game would go, remember this is all just from personal experience, and you can always ask me if you have any questions!