How to win the game
If your team has taken mid turret and mid inhib, STOP going mid lane, pushing and hanging around in their base. Stop going mid and trying to team fight for no reason. Shift your attention to other objectives such as side lane turrets or dragon /baron. I've seen so many low Elo players lose games because they spend so much time aimlessly wandering around mid lane after the turret and inhib have been taken. This is the best opportunity for your enemies to comeback because you guys fight and die while accomplishing nothing.