How to get out of silver?

Pick a small pool of champions, not mechanically complicated.
Best idea would be to play jungle / top and learn champions that works both lanes.
Don't be afraid to try risky plays.
Don't press yes to surrender votes. (this is situational, as long as you need to know what fights to pick you need to know what fights can't be won. but i had and seen comebacks from 12hp nexus).
You can also try playing a single champ (OTP).

A good example is Pantheon that works both jungle and lane, can snowball, has decent mid to lategame in terms of decision-making / macro.
Is a guy that hit challenger and rank 1 in 3 seasons only playing it.
Using the ultimate for ganks is very efficient , especially with a duo that can time a CC ability to make sure you hit him with the ult.

If playing duo don't go on the same lane (BOTLANE) , one mistake from one of you can cost both your chance to do something.