How to improve in league

I have been trying to climb out of Silver and keep going through patches where i reach a tier, or possibly a new tier, but then i go on a loss streak. I usually try to do Viktor or Anivia mid lane and sometimes I smash the lane, other times I manage to prolong the enemy team from taking turret. Some games my team isn't doing so well and I want to go gank but I dont know if it would be worth the chance of losing tower. I would love any advice or even some tips if you look at my games to help me improve because I do want to hit gold before the end of the season. Should I try a different champ mid lane or try doing a different lane? I do Alistar for sup if I do get autofilled but I feel like i can contribute more if I'm in a place to help out other lanes. I do take ignite for kill pressure but have been wondering if I should take TP so I can make last second ganks to turn the tides or even split push. Thank you for your time and any tips you decide to share.