Only cook what you plan to eat and in small amounts. We usually like to do things in batches, so for example, if we are going to cook shrimp, we ask everyone who wants shrimp and we put in only the amount that is being eaten. That way we know that all the shrimp will cook at the same time and you won't have any leftover overcooked shrimp sitting in the pot during the whole meal. The only exception is the frozen paper-thin meats, since they only take 30 seconds to cook, these are usually cooked on the fly by whoever is going to eat them right away.