Hello friend.
Let me attach a disclaimer to this saying that I main Top. However, I do play a fair amount of Support, as it's a nice break from the constant brain strain that is laning, and it's good practice for maintaining map awareness.
Now let's get to it. So, you want to climb right? Climbing out of Bronze isn't hard, but it isn't exactly easy either. The best way to climb out of Bronze is to carry your way out. "But Tom, that's super obvious! How do you do that?" Well there's a foolproof way to carry in Bronze. It goes like this:
1. Crush your lane
2. Win Team-fights
It's that simple. But to do that, you should change up your champion pool. There are two key attributes for supports that are king in low elo: Damage, and Hard engage. I have nothing against "supportive" supports like Sona, Soraka, and Janna. They're all consistently good picks in all ELOs. But the thing about these kinds of supports, is that their effectiveness scales relative to the skill of the ADC. Let's be honest here, if you're in Bronze, your ADC is most likely a potato. You want to make your potato ADC's life easy. This is why you want to switch to supports that kill the enemy, or make it easy for your team to kill the enemy.
**Damage** - *Zyra & Brand*. These are the two main picks that deal tons of damage with the least of amount of gold. Zyra is probably the most oppressive laning support in the game right now, with the ability to throw out tons of harass with her plants, as well as having good pick potential with Q and disengage with R. Get a sightstone, then go Sorc Shoes, Liandry's, Rylai's, Void Staff, Zhonya's/GA. Tons of damage and poke. You're essentially a mage with a little more utility.
Brand is a little different, in that while he's not quite as good in lane as Zyra is (he can still do a ton of damage if he procs his passive), but he can absolutely *crush* team-fights because of the % health damage on his passive and because it spreads between enemies, doing tons of AOE damage in a fight. If the enemy team groups, Brand will destroy them, and we all know, people LOVE to group in low elo. Same build as Zyra, swap the order of Rylai's and Liandry's.
Other good picks - Vel'Koz, Lux, and Morgana.
**Hard Engage** - *Leona & Blitzcrank*. I love Leona. She's basically a portable GO button for any fight you want to take. Extremely powerful gank setup, and snowballs super hard since she can picks fights any time she wants. If you see an ADC or enemy carry out of position, Leona will make sure she doesn't get away with that. Plus she's so good for starting favorable fights/getting picks. Just spam ping your team that you're going in. Typing in chat "I'M GOING IN," do what you need to do. Just make sure they're following up. Because Leona will lock you down if you're an ADC and you have the nerve to step out of line vs her.
The thing about Blitzcrank, is that in low elo, he's god-tier. You can miss nearly every single hook in the game as Blitzcrank, but all you need is one good hook. One god-tier hook. It can be straight dumb luck, no one cares. Pull the enemy ADC into your team, and the game is over. Blitz is straight up the best pick champ in the game. If you hook a squishy into your team, they have to blow flash, or die. Blitzcrank wins games off of hooks, and pressure. Just the *threat* of a hook will scare your enemy into playing passively, especially if they're playing squishy champs against you. Just one good hook, and you won lane. Just one good hook, and you won the game. All you need is one.
Other good picks - Malphite, Nautilus, and Sion.
Even if you didn't read anything before this paragraph, I just want you to know that when you play in SoloQ, you should know that while you're in Bronze, your teammates are also in Bronze. They don't hate you. I consider them potatoes. They are friendly, well-meaning potatoes, though. Your job as support, is to pluck your potato teammates out of the ground, and carry them to the market (the enemy nexus). There are many ways to do so, but I'd rather carry potatoes in a wheelbarrow than with my hands.
Oh yeah, and general stuff. Ward, ward, ward. Buy a sightstone, please. Ward early, ward often. Once you win bot turret, look to pressure mid. Protect your carries and yourself first and foremost, can't do any damage if you're dead. Be smart about engaging. Objectives > Kills. Get infernal & mountain drakes. More damage = good. Ward, and ward more. Ward.
I took way more time writing this than I expected, but I was having too much fun with it to stop. I hope you enjoyed this and learned something from it. Good luck :\^)