Some help please!

Hi guys, I want to let u know that im in love with the game as most of us. I' m currently ranked in silver 3 but i want to get higher. I used to play in every position but now I'm trying to master mid and adc. I farm about 70cs in the first 10 mins, which I think is good enough. I ' ve been playing since November and I' m lvl 30 for a month. Most of the times i win the lanning phase with 2-5 kills and 0-2 deaths but after this I' m completely lost: Don't know when to team-up, how to end a game and teamfight positioning. What I am asking for is some advice on those 3 things. If a plat< sees my post could he comment his name so I add him in order to give me more in-game advice.

Thank you all a lot, hope you win and have fun. Keep LOLing