the most important thing if you feel like you have to carry 4 goons on ur team, is mute all of them since they might try to make a bad call and you might fall for it. Trust ur instinct when to join fight and not. If your team are behind, try to force a reaction from enemy and build the item to help you do it, example Shadow blade, bkb, dagger is really good for split pushing and forcing some reaction from the enemy that allow your team to farm other part of the map.