For me the most helpful thing I learned was to give every character “a thing”, some very specific trait. Whether they are very into board games, or just found out their 23 and me details and are trying out a bunch of new accents. This helps guide each character to feel unique and individual whereas a lot of scripts you can take the names off and you’d have no clue which person is talking because they are all similar. And in the final draft you might dial it back but it’s good during the writing process to have a guiding light for each character.