I climbed from Bronze 5 to Gold 4 in one season just by deciding to learn the game and practice. You'll get there, just keep at it. Here's my advice.
1.) Vision
Wards
Always standard warding trinket until your support item upgrades to have wards, then swap to the sweeper.
Do not buy a control ward right away, the health pots are more important with your first 500 gold.
From your first back and onward, you should be trying to buy a control ward. Note that they are useless if you cannot defend them and the enemy will be able to clear them out easily.
Ghost poro really isn't that good, especially on support. It's more useful on junglers and assassins. If you want, zombie ward is pretty much better in every way.
What bushes and regions are commonly warded? This is one you should probably should google, but here's the skinny. For laning, ward tribush or riverbush depending which side you're on, if you're pushed up or pushed in, what kind of jungler the enemy has, and what route you think they'll take to gank you. Later in the game, warding the bushes in the middle of the river, the bushes between red buff and dragon/baron, and the bushes to the side of mid lane are good to keep clear. Also, don't forget to ward baron and dragon when they're up.
Bushes
Alternatives to facechecking, assuming I have no mana and no wards left? Throw a skillshot into them, see what happens. Alternatively, start to walk up, then juke to the side anticipating their skill shot.
Is facechecking ever a valid method of searching the bushes? Not really, no. If your spidey sense is tingling (which will grow as you learn), it's not worth it. If you're walking through your own jungle and your team is super ahead, then you can probably assume they haven't had a chance to get in, but just be on your toes.
Precautions to take if I decide to facecheck a bush? Be with teammates. Be playing a big tank. Be ready to anticipate a skill shot.
When to hide in a bush in lane? Most of the time. If it's not warded, they can't see you winding up for a skill shot. They don't know if you're at the front or back of the bush, so they have to play as if you're at the front, sometimes using mana to check it with a skill shot. You can also force them to use a ward on the bush, which is another ward they aren't putting in the river.
If I know they warded it but I have no sweeper? It is still good to have control of the bush because then you don't have to ward it.
If I don't know they warded it and I have no sweeper? Yes, control the bush. You can also check if the bush is warded by drawing agro from a minion or two and walking into the bush. If it's not warded, they'll stop because they lost vision.
Freecam
How to handle the clunky controls? Practice until it's not clunky.
When it's worth it to use freecam rather than just the minimap? All the time. You can see easily what cooldowns are being used, exactly how people are positioning, and how the minion wave is behaving.
Is it bad that I almost never freecam at all? Yes, change that right now. Practice in bot games if you must. Get good at using free cam.
Junglers
How to avoid ganks? Ward. Stand near the bottom of the lane. If you're pushing up, ward. If you see the enemy jungle top and the midlaner isn't roaming, save your ward for about a minute after the jungler leaves top lane.
Wards don't seem to make a difference, since if I'm in a place where I'm liable to be ganked, I'm probably also at 30 hp and cc'd into oblivion? Then don't do that. If you're liable to be ganked, back off and recall.
How to know what's a bait in disguise and what could actually be a good trade? Wards. Also, practice. Learn to notice changes in behavior. If the Janna has been hiding 2 screens behind her ADC for 5 minutes and all of a sudden walks up to W you......something's fishy.
Just as a general tip, play some jungle yourself. I queue fill most of the time in ranked and I'm placed jungle about 15% of the games. Playing jungle helped me learn jungle timings, routes, etc. Learn your enemy and you'll learn their patterns and weaknesses.
2.) Playstyle
CS
Is it ever acceptable as a support? Only if you have relic shield stacks. Sometimes your adc is coming from base, but there's almost always something better for you to be doing. Also take into account, the support items may soon be changed to have all gold income disabled when you kill a minion.
What should my farm be by the end of the game? You are are the support, you do not last hit, it is not your job, you do not have a farm goal.
How to build when all your gold income is based on one item? This is not the problem you think it is. Supports items tend to cost less than other main roles. Also, your gold income should not impact how you build since it will be fairly steady compared to other roles.
What is my job? Make it very easy for your adc to CS. Play some adc and learn how to CS under turret. Sometimes it will be helpful to auto a minion once or twice so your adc can last hit it. Also take into consideration that the enemy wants to last hit. Watch your own minions. When one starts to get to low health, the enemy adc will walk up and auto it, making it the perfect time to harass them.
Aside from destroying wards and placing them? Do this as much as possible, which is why control wards and sweepers are important.
What to focus on early/mid/late game? Depends on what champ you're playing. With Blitzcrank, feed your adc early game. Roam through into the mid game to give your other laners advantages. Late game, hook the enemy carries and win. When you play someone like Janna, never die. Use your abilities to keep your carries alive. Peel them with Q and R while shielding them from key damage with E.
When to back? Do NOT back if your minion wave is pushing. This is when your wave is bigger and will kill the enemy minions faster. This means your minions will make you lose all the cs and xp from the enemy minions that die. Instead, try to push the wave all the way into the tower. Then, the wave will crash and push back towards you. That means the wave of enemy minions will build up just in time for you to get back from base. Additionally, the enemy will lose out on getting to kill your minions. Controlling minions waves and getting good back timers are huge in pro games, so watch those if you'd like.
Especially if the enemy laner is still doing well in terms of health? If you back with a huge wave under tower, that feels really bad. Back if you're going to get dove, but they'll most likely get tower. If it's really bad, you'll most likely need your jungler to come and help hold your tower up and clear the wave. Most times, just try to play super passive until the enemy runs out of mana or gets lots of gold, then decides to back.
Do I all-in them and force them out of lane? Didn't you just say you're low on health? Why fight into the enemy's advantage and risk giving a kill?
Do I bait them near my turret by backing and then ask my jungler for a gank when they push? Do not rely on your jungler for a gank, most of them are stupid. However, if you are pushed in, you are more likely to get a gank since it's easier on your jungler, so it's a good idea, but don't be shocked if they ignore you.
Should I ever back because of mana/hp, or should I wait for that to regen? Yes, if your mana or HP is too low, you won't be able to fight effectively and will most likely die if the jungler shows up, or even just die 1v1. Learning to manage your mana and health takes practice and is also why you take health pots early in the game.
When to buy? Whenever you are hitting an important item spike. For example, on soraka you could back to buy ardent censor. Also, if you have a large amount of gold, say 2000 more than the enemy, but it's sitting in your pockets and your enemy just bought, then you DON'T have a gold lead. You are equal on items and strength until you actually spend the gold. It's usually a good idea to match your opponents backs so you stay relatively even.
Is it worth building an item rather than just buying it straight up? A completed item is virtually always worth more than the sum of it's parts. That being said, it costs the exact same if you buy it one piece at a time and build it slowly or if you get it all at once. It doesn't matter. So, complete your item if you can, but don't be afraid to spend what you have because you might as well get that small bonus if it will build into a larger one.
How to know what to buy? This is a really good question. That's partly situational to your champion and partly to your and the enemy team comp. Take boots for example. On Blitzcrank you always go mobility boots. On other champions, you may want to go Ninja Tabis if the enemy is AD or auto attack focused, Mercury Treads if they are more AP and CC focused, Lucidity boots if your build doesn't have enough CDR in it, Magic pen boots and Attack speed boots if they're useful and you can get away with it, and mobility boots to engage or roam. Swifties are even more situational, so don't worry about them too much.
Now that was just the boots. I can't go into every single one, but just know please don't rely on mobafire. Use either probuilds.com and/or op.gg. However, a word of caution, you must still learn and know WHY those items are bought. No one "build" is universally the best option on any champion. Many champs are like Garen where you build one "core" item first 100% of the time (black cleaver) and have many options after that depending on the situation. Learn the strengths, weaknesses, synergies, and purpose of every item, or at least the ones built on the champion you want to play.
Now, I've almost reached the character limit, so I've put the rest in a reply to this comment, see below.
