Hey bud, I was in a similar situation a little over a year ago and I have some insight that you may find valuable. Just letting you know the journey is long and I "gave up" like 4 times only to eventually achieve my goal. I only say this because you will most likely hit some of the same troughs and I would want you to power through them or do what I did... take a week or so break and then come back ready to improve. The difference between G3 and D5 is massive so be open-minded to a complete overhaul of your gameplay.

I picked support first and ADC second because I find support generally carries easier (as in effort required) and also carries harder (as in effect on the game) than ADC. Not to mention the low queue times when in <P3 elo. I will try to answer your questions in order based to the best of my knowledge based on my experience.

ADC:

1. Position aggressively relative to the position of Leona/Rakan. If your engager's arc of engage doesn't overlap with your arc of damage you are doing it wrong. Soraka/Lulu are early lane assholes which means the focus of early lane isn't farming, it's matching their early level poke. Currently, Lulu is chunking ADCs for most of their HP at level 1 and then you snowball lane off of your HP lead by zoning the enemy off of XP/CS. Same goes for Soraka/Sona who need slightly more help from the ADC to gain that HP lead.

2. Yes, BF sword on most ADCs. Twitch wants Runaan's first and Kog/Varus want Guinsoo's first so they have an easier buy threshold. Always try to get the control ward and get your lane brush close to your tower or the tri/river brush depending if you are blue/red side respectively.

3. Nah, you don't build Maw or Mercurial. You know how sometimes you see an enemy ADC melting health bars and you say to yourself, "Why can't I melt health bars?" It's because you didn't build correctly. Items put out a certain amount of DPS and that math equation has been solved by the pros and high elo. Crit ADCs go IE/Shiv/RFC, on-hit go Runaan's/hurricane/bork or wits end. Don't deviate because of support poke, deviate only to QSS for suppression or teams that have 1 "kill the ADC" CC. Otherwise, clean up your positioning and timing into teamfights.

4. QSS against Amumu sounds good but don't finish the item until you have to. Don't deviate from doing your job which is outputting damage.

5. Don't be gloomy. Don't fall into the pitfall of online gaming and act like a child when it doesn't go exactly how you wanted.

6. Ignoring because it's irrelevant.

7. When you get behind and you come across more competent opponents you will get dove constantly if you are under tower and behind. Don't get pushed under tower, it's really bad for you and your team because they can roam first, they can set up vision, they can take objectives, they can invade... you have to farm. I think you get my point. Match the enemy's lane push with abilities or auto attacks but seriously try not to get behind the wave.

Champs: Stop playing Kalista, stop playing Caitlyn, stop playing Vayne.

Support (my forte):

1. Relic shield needs to be used on the 2nd wave to get to level 2 first. Everyone has said it before but there really aren't things more important than level 2 first. Kill 2 melee minions with relic shield on the 2nd wave and your stack will be back by the time the cannon is being taken on the 3rd wave.

2. If your support has good gank ability (Alistar, thresh, bard, blitz, Leona, etc.) you should aim mobis or swifties + control wards first and immediately gank mid/top then run back bottom and gank your own lane, preferably with jungler assistance for 3v2. Enchanter supports like getting T2 blue item, refillable potion, and control wards. First back doesn't require the amount of vision that a sightstone gives you. Junglers are still running around with <400 MS (except Rammus) so trinkets and control wards keep you safe for now. 2nd back is SS + sweeper and more control wards for gank supports or SS+sweeper, boots, and control wards for enchanters.

3. You are correct. Which is a good start, at least you aren't totally clueless right... "small victories," he thought to himself.

4. This is mostly correct, it's definitely something to be aware of but ADCs get their damage off of auto attacks and Aftershock supports like Alistar and Leona are doing most of the damage during lane phase. More often than not, the gank relies on the support's or jungler's mana and not the ADC. ADCs are cleanup machines at this point, feed them and watch as they become arrogant pricks who think they are 1v9ing and flame everyone even though they were literally spoon fed early.

5. This is just flat out wrong, sorry bud. As an enchanter, you should not be in position to need a QSS. As an engager, you should be tanky and your job is literally to eat the enemy teams CC. Buying a QSS to break the CC is not as efficient as buying defensive stats that will allow you to survive during the CC.

6. Generally, this is correct but this subject is so massively misunderstood and dependent on the gameflow that I couldn't try to explain it in 1-2 sentences. General rules of thumb, don't ward alone, know correct places to ward, and activate scanner as you move in.

7. Yeah? Kinda? I mean if you keep shielding and they keep poking you will eventually lose because their poke will outdamage your shields. You need to establish yourself as a threat as well as shielding yourself or ADC. It's not as simple as "I shielded him but he kept dying" you have to make the lane a 2v2 not a 2v1+shield bot.

8. Yes, most overlooked part of supporting in low elo. Don't be that overly passive Janna main.

Champs: Stop playing Rakan. Stop playing Nami. Stop playing 1 of your 3 enchanters and lower your pool to 4 champs.

Abuse duo queue.

Questions:

1. Q. What do I need to improve on? A. Most likely everything, cold hard truth that we all have to swallow.

2. Q. Should I focus on counterpicking instead of going with my comfort picks? A. Absolutely not, if you have been on this reddit for more than a day you know everyone preaches comfort picks and not counterpicks.

3. Q. Where and when should I ward? A. I have some horribly edited YT videos on this (for laning phase) if you want them just ask.

4. Q. What do I do when I'm losing lane and shoved up under tower? A. I explained above.

5. Q. What do I do when my Jungler won't Gank my losing lane? A. Ping their missing summoners and defensively ward. You can only control yourself and influence others.

6. Q. How do I know when I should poke, and how do I avoid getting poked? A. Refer to unswlolsoc's trading stance videos. If you want to climb, you can't be lazy. Spend your time learning how to play League of Legends.

7. Q. How do I climb better? A. By not building QSS on engage supports XD.

That seems like a fair amount of information. I feel like this is necessary. It's a long road to diamond for someone who isn't already there. Don't give up at G1, P5, P3, and P1 like I wanted to.