Explore Mother Base
Konami has mentioned that events and encounters will unfold at Mother Base, and there are a ton of things for you to do in-between missions. Going up to your soldiers and saluting them, for instance, will help boost that soldier’s morale, as well as the overall morale of your entire base. Exploration of Mother Base will also allow you to find random raw diamonds scattered around the area.
Snake’s actions will influence the development of Mother Base and the Diamond Dogs, so players have to step in occasionally, and resolve any possible conflicts that may arise. This will help to maintain order on Mother Base, and keep your operations running smoothly.
In addition to that, you can also eavesdrop on your soldiers’ conversations. The nature of their conversations seems to be random and you might even glean some useful information from them sometimes.