League of Legends is a team game.
The most you can do, is improve yourself so that you make little to no mistakes.
As soon as you can do that, I can guarantee your rating will improve.
When the new Ranking system started early February, I was placed in Silver I.
I dropped to Silver II from a few bad matches, but after focusing on minimizing mistakes and choosing champions that have a strong impact during teamfights, I made it back to Silver I.
Using the same mindset of "How can I improve?" and "What are some mistakes I can avoid?" I was able to climb up to Gold I, which I am now. So in a matter of 2 1/2 weeks, I climbed from Silver I to Gold I. I'm more than excited to hit Plat V by the end of this week if not sooner.
I suggest three things you do every game, and I guarantee you will win a majority of your games.
1) Aim for 0 Deaths.
2) If you die, figure out the mistake you made and improve on it.
3) Don't flame your teammates for "being bad." No one is perfect and EVERYONE makes mistakes.
Always remember to have fun.