This will be a shorter entry in this series, mostly due to the fact that the book lays out the procedure for determining the exact values of each entry. What I will focus on instead is choosing the kinds of conflicts your creature will have disposition values for. As with Nature, we want a mix of dispositions that support the concept of the creature.
I find the easiest way to achieve this is to look at the creature's Nature Descriptors. In fact, I would caution that this step in building your monster cannot be completed until those have been assigned. Each descriptor should point towards one or more potential types of conflict. If they don't, or you find that you're only getting a few types of conflict out of those descriptors, this is a good indicator that your concept needs some tweaking. The book reminds us, "Creatures who want something become puzzles to explore and solve. Creatures who only want to fight rapidly become tiresome."
Finally, be conscious of how many dispositions you assign your creature. For most creatures, I find that three is the perfect number, as it allows you to assign it a strength,a competency, and a weakness. For the more difficult creatures, absolutely assign more, but just note that this will increase the difficulty of the encounter