Before diving into high-fidelity mockups and fretting over every pixel, most projects require some sort of understanding of how the data in a set of designs is going to be organized.
How does a user encounter this information? What is the hierarchy of this information? Where does the data come from? Can a user modify this information? These are critical questions that need to be answered.
To get answers to these questions, its a good idea to document some of the key decisions and get feedback on the feasibility of how this information is being conceived before spending too much time on design. Most of the time, these decisions and the feedback collected from this documentation informs design decisions, creates directional alignment, and sets the whole project up for success.