In the comments yesterday, Alice asked about the mantra -- a hero leads. And does it apply to a heroine as well. And across all lines.
In this case the mantra -- a hero leads applies equally to both the hero and heroine. They both need to be proactive and willing to take charge of their life. Things do not happen to the main characters, they make things happen. Then when the world does not react in the way they expect, they take action again. It also applies across lines. The main characters must be willing to take life on and to make things happen. They are the ones who make choices and who have to live with the consequences of their choices. They do not simply sit back and relax, or become overwhelmed. Proactive rather than reactive.
You do not want your hero or heroine to be overtaken and overwhelmed by events. What ever happens, they remaining fighting against events and not simply accepting of the status quo.
They may be in statis until the inciting incident, but once the story starts, they take a lead.
Main characters need to be assertive rather than passive -- even though they might appear to be without power. Daphne du Maurier does this brilliantly with the second Mrs de Winter in Rebecca. Because most of the book is a memory of an older woman, and the author keeps giving subtle hints about how she is now making most of the decisions, the reader can accept the narrator's naivete etc in a way that had the story been told in real time/a linear fashion, she wouldn't.
One of the problems with the current Viking is that events kept happening to the hero and heroine, rather than them directly influencing events. This made my editor question why the heroine was so timid. Some of it had to do with the heroine's back story which had to be changed and some of it had to do with how she approached things. Rather than sitting around waiting to be rescued, my heroine at least had to have a plan of how she was going to escape.
Sometimes, it can be simple, for example, I originally had Ivar being far more rational about certain things. He had argued for more ships. In the revised version (which works better), the expedition is his idea and he has argued that one ship has a better chance of getting through.
Another way of saying this is Make the Turning Points Active. The vast majority of your turning points must be a direct result of actions by your hero or heroine, rather than by events beyond their control.