There's an old saying, "Rome wasn't built in a day." If you want to improve & "git gud" in League of Legends, here's some tips that could help.
- "Have Patience" : You're not going to get placed in diamond elo over night. Its going to take alot of time & practice to get to the top, as cliche as that sounds.
- "Do your homework" : Keep a close eye on the meta. If you see something that's strong or flat out busted (I abused Brand/Veigar Support for this Season & Season 7), practice playing it & apply what you learn in ranked when you feel ready for it. If you need advice, tips or just need help in general on playing as/against a champion, don't be afraid to ask the boards. There's plenty of players here that have extensive knowledge that I'm sure would be willing to point you in the right direction.
- "Dreams begin small": Know that not everyone is Diamond/Challenger material (take this with a grain of salt). However if you feel like you can make that daunting climb up the ladder, just make sure you have other goals on the way up. If you just make getting diamond your ONLY goal, your going to be putting alot of stress & frustration on yourself. Set smaller goals like "Make it to Gold" and "Make it to Platnium". Sure you might fall down a Division or tier at some point, but it's all trial and error.
- "Prove them wrong": If someone sticks a finger in your face & tells you that "You'll never be good, just give up", would you rather accept that as a fact or use that as Motivation? I had a friend once tell me that I would always be Bronze/Silver trash & would never make it out. Instead of just taking that as fact, I used it as a driving force that got me to Gold in Season 7 (I even beat him to Gold ELO to put icing on the cake). A quote from Sylvester Stallone: "It's not about how hard you hit. It's **about hard you can get hit and keep moving forward."**
Bottom line, anyone can be good at this game. It doesn't happen overnight, but you will play better the more time & effort you put in. Don't give up & don't be afraid to fail.