Mistake #3: Skipping post-workout fuel/meal.
As athletes who often do daily double workouts, recovery is paramount not only to performance, but also to optimizing immunity and minimizing injury. Make it a priority to consume 2.2–2.6 grams of carbohydrate/pound body weight in the hour post-workout—even after late-evening workouts! Include some protein (and a pinch of salt) as well to help muscles repair and rebuild stronger. Wash it all down with some much-needed fluids.