I guess further discussion would need some specific examples.
But I do play heads up mostly, and when I refer to calling stations, it is guys that rarely fold a flop and often call a turn. That leaves them too weak on the river to call a bet.
I can't imagine it being so different in a tournament, if a guy is calling with gutshots and misses the river, is he calling your river bet? If the guy is calling with two high cards, is he calling the river when he misses?
Those are the types of hands that calling stations get to the river with, and they just can't hold up to a lot of pressure. They don't call because they think they are best or because they don't want to lose chips, they call for the hopes of winning big (like many bad players do). Once those hopes are gone, you can successfully push them out of the hand I find.
Now, if we're just talking about players that call with bottom pair and draws, that can be a different story, but still, I would encourage even the newest player to start learning about board textures and recognizing when and where you have a better chance of pushing a player off of a draw.
Good players need to learn to bluff quickly, it's not that advanced, and if you aren't caught bluffing very often you are unlikely to be bluffing enough. It's just scarier to some to get caught bluffing, but often things like missing a value bet or calling an extra street with a weak draw are far larger mistakes than bluffing a bit too often is. A lot of disciplined new players just tend to get too passive rather than too aggressive I think.