LF Coaching (Silver Mid/Jng Main)

Hello, I am a Silver 5 Mid Main wanting to improve. I have another account (http://na.op.gg/summoner/userName=Unseen%20Zed) that I played on a lot throughout the mid season, it started in Bronze 4 and Now is silver 5, but I peaked it at S3 Promos. It had a positive winrate for a long time but now its at 49% with about 300 games played.

I also climbed this account from Bronze 4 to Silver 5, I just demoted today and I just can't seem to win a game. (http://na.op.gg/summoner/userName=plutoniumlol)

Anyway, I'm plateau'd and I haven't been seeing any improvement even thought I play a lot. So I'm just asking for the help of any high elo player that wants to help me improve at the game.