Hey I'm only a Gold V Jung/Supp main but as I just recently got to Gold through my placement matches at the beginning of S5 I feel like I have a good grasp of what exactly brought me from Silver to Gold. 
 I would site 3 things that directly affected my play positively. The first of which was reducing my champion pool. I'm on my phone right now so I can't check your OP.GG to check your champions played but my advice would be to stick to Rek'sai as much as possible. I think she is a good champ that can be built in a variety of ways depending on what is needed and I think that is a great tool to have at your disposal. Sticking to a smaller champion pool will increase your skill and knowledge with those champions. Picking counters because a website told you "x counters y" does you no good if you can't play that champ. I played Maokai jungle as my main when climbing to gold, he is considerably weaker in the jungle than many champs, but I knew him well and enjoyed playing. My knowledge of hook allowed me to focus on other things as well as maintaining a strong grasp on the limits of my champ. The second thing I would focus on is vision. I can not stress enough how important it is to upgrade your trinket and make sure your team does so as well. From my experience players Gold V and below do not ward enough to warrant a red trinket, unless of course you build SS. Vision is your best tool for helping to know when it's safe to gank a lane or when you need to counter gank, which given Rek'Sais global ult is incredibly potent. For 250g you can make more of a difference than any other item could potentially buy by a long shot. The third and final thing is a question i started asking myself with every decision I had to make "Why?". Why are you building this item? Why does bot keep getting ganked? Why should I build tanky or damage? Always ask yourself why you are doing something or why the enemy is doing something. It's easy to watch an LCS game or a high Elo stream, the key is to understand why they are doing the things they do. Apply this question to everything from champ select to end game vision control and especially to watching replays if you decide you want to do that. I am by no means good at this game but I made a mindset change earlier this year to make the push into Gold and I used these tools to help me get there. I hope this is helpful in some way, feel free to PM me and I would have no problem playing some normals with you if you're on NA. My internets been spotty so I've had to take a break from serious ranked play until I get it fixed. IGN: TooFratToCarry    NA server.