ADC is a hard role to play at lower ELO's, Bronze to Low Silver. If you really want to play it though you can practice a few things to help you improve. Just note that I don't play ADC, but I am familiar with a few basic tools required to play the role.
- CSing is key on an ADC, this is how you get the gold for the items you need.
- Trading is a big part of Bot lane, you need to learn when and how to trade.
- Positioning with an ADC is incredibly important, specially during Teamfights.
- Don't be alone! This is a huge issue I see in low elo, ADC is off alone farming and dies for it.
For now all you really need to work on is CSing and Positioning. If you get better at those two things, you will easily climb out of Bronze.
You can practice CSing by going into a Custom Game and farming alone. Farm for about 10 minutes, try to reach around 60-80 CS by the end of 10 minutes. If you can't, start over and try again. If you can hit that marker, start over anyways and try to improve it. I think at 10 minutes there are around 100-110 minions (i can't remember off the top of my head the exact number), so you want to eventually be hitting as close to 100 as possible.
Once you can consistently hit around 80-90 CS by 10 minutes, try adding in a Bot into your Custom Game. Then try to hit that same CS marker with an enemy in lane, do this until you can do it consistently. If you want to practice trading, you can do it at this point as well. You want to attack the enemy as much as you can without missing any CS and taking as little damage to yourself as you can. A good moment to trade is when they move in to last hit a Minion, they will be more focused on getting the Minion than on you, so you can get easy trades like this. HOWEVER! You don't want to lose CS! At this ELO, CS is your lifeblood, it will be how you carry yourself out of Bronze.
As for Positioning, that is something you more learn through playing with a champion. You learn their maximum range and therefore how far you can stay back and still be relevant in the teamfight. You want to position yourself in a way that their Carries can not attack you, for now you should prioritizing on not being attacked by enemy carries. There is a lot of mechanical and decision making skill that goes into Positioning in a teamfight, but for you all you need to worry about is not being killed immediately. If you followed the first advice, chances are you have a ton of gold and can almost just AFK attack them and watch them melt.
This next piece of advice is important for all roles or champions you play, STAY CALM. You are going to lose and lose and lose, but if you stay calm and don't let it effect you, you will win twice as many games as you lose. Don't blame your teammates, look at yourself, what did you do wrong and where could you have improved? You gain nothing by blaming your teammates, but you have everything to gain by looking at your own mistakes. If you feel yourself get tilted, don't worry that is natural just stop playing for a bit. Playing while angry or tilted will just cause you to play bad and you will most likely lose.
So remember just stay calm and cool, if a teammate makes a mistake just ignore it, you are going to see a lot of mistakes in Bronze. If you didn't make mistakes you wouldn't be in Bronze. Trust me it is actually very easy to climb out of Bronze once you focus on improving yourself and less on what your teammates are doing. This will also help you in Silver, because Silver is harder to climb out of than Bronze is.
Good luck and I hope you can end up climbing. Also if someone contradicts what I am saying, you should probably listen to them because I am just a Gold V noob with a lot to improve on myself lol