Thats pretty much the name of the game. Best bet is to pick one champ and carry the fuck out of it.
Some stuff that should be obvious: Objectives and Towers > Cs > Deaths > Kills. Prioritize and it'll be alot easier to carry.
Learn high mobility/damage champs. The more influence you have on the map the better.
Just doing that brought me from b5 to b2. Working on B1 this week.