Your Yang energy (Qi) changes to Yin around 11pm when it is time to rest, and switches back to Yang at around 11am. Managing these shifts with awareness helps you move through the seasons in as healthy a state as possible. In autumn especially, go to bed early (which helps retention of Yang Qi) and get up early (which allows the lung Qi to expand and sets the mind at ease).
If you have a warm constitution (i.e. a Yang body type) you may be prone to dry skin and a dry throat, especially in autumn. Consume cooling, re-hydrating foods to reduce internal heat and nourish your lungs, eg pears, persimmon, starfruit, lily bulbs and buckwheat.
If you have a cool, Yin constitution, you are more prone to colds, and your body may get dry and lethargic because of the nature of the air you breathe at this time of year. Warming, fortifying foods that will help you are, for example, passion fruit, grapes, longans and peaches.
Sour tasting foods retain the Qi energy in the lungs whereas spicy foods dispel it. So as a general rule, in the autumn, you should go for sour in preference to spicy foods.