Sentence:  She dismisses Littlefinger's advice to prepare for every possible outcome and see the world as a place of unimaginable horror. Littlefinger is telling her to be a little more like Cersei, always <WSD>two steps ahead</WSD>. The difference between Sansa and Cersei is that she has no desire to repeat what has been done to her as an act of vengeance. 
Meaning of the word marked with <WSD> tags:  Having cleverly anticipated what others will do or think.