Well lets me start with how to improve in general. I do not know your role, but with anyrole, pick a max of 5 champs to master. Thats it. You will not play any other champs. For instance i main mid, and i have 4 champions i pick between. Ryze, Leblanc, Lulu, and Ziggs. Once you have picked what champions you want to main, you need to learn them. Sounds obvious. really it is. Basically learn how much damage you output at certain periods. "i know with 50 ap, that i can kill my enemy with my combo if he is lower than 60%." etc. learn your combos, damage, when are you weak, when are you strong. That you get from playing games. You could also watch others for parts of it.
Improving your cs is another big thing. Ill be honest there are times where i'm not doing to hot mid, i may have died a couple of times. If you farm well, the kills don't matter. I was Leblanc the other day vs a zed. He had a shaco jungle and i died 3 times in the first 15 minutes. 15 minutes in the zed had 2 of the kills and he had 90 cs. I had 115 cs 15 minutes in. A kill is worth about 12-17 cs, for this lets say 15 cs. with the 2 kills and 1 assist, which is worth about 7 cs. The zed was only 12 cs above me in gold. or about one kill... Go into a custom game without bots and keep csing. Solo, aim for 80 cs by 10 mins, and 160 cs by 20 mins. Now add in bots to the game. Practice till you can do the same thing. If you can't get 60 cs in 10 minutes, you need to practice. If you try this and you are unable to improve, then silver is where you are meant to be. Next i will skip to smurfs.....smurfs arent a problem. They are super rare and you will almost never run into them. People may say they are smurfs, but most are not. I am called a smurf on occasion, and i just say "i know what im doing". When there is a troll, afk or whatever. Right then accept the game is a loss. harsh world but hey, 4v5, not worth getting upset over. You will lose lp, which honestly is BS. Riot's ranked system is the worst ranked system possible. They need to fix it so the afker loses all the lp the team would lose. That way leaving the game would be heavily discouraged. When i experience a game with an afk, Instead of trying to win, i change the rules of the game in my head. I start a mini game with myself to see if i can have a little deaths as possible. Focus on not dying in a 4v5. thats it. When it comes to real games, that will also help you. ......If you are not having fun, then you can play normals, or play another game. I take breaks from league occasionally. ....Another big thing for climbing is tilting. If you lose a game, no matter what. DO NOT PLAY ANOTHER. wait at least 30 minutes. Calm yourself down, get into a better mood. Then play a game.
If you lose after that. your done for the day. Find something else to do. Or play normals for the rest of the day. Lastly, look at what time of the day you are winning and losing. For instance, for me personally i have a 90% win rate between midnight, and 11 am. from 11am till 3 i have a 60% winrate. 3pm to 8pm i have a 40% winrate. and then from 8pm to midnight, i have a 10% winrate. I avoid playing between 3pm and midnight at all cost.
Another quick think to add is go to youtube and search for scrapcomputer......watch all his midlane and jungle guides.. I dont care if you a top, mid, supp, jungle, adc main. you watch all of them. that is a good 10 hours you put into the 5 guides he created. Those 5 guides are equivalent to months and months of playing the game. Understand the game, understand what your teammates should be thinking, understand what you should do when. Record games you play and look for what you did wrong, there will always be at least one thing, and improve it. "instead of getting that camp, i should have ganked top here"