Get lots of rest

Make sure to drink lots of water (water should be room temperature, not cold)

Herbal tea is good if you need something hot. Try not to make it too hot

If your throat feels really dry when you wake, gargle with a light salt-water solution

Try not to gargle with mouthwash that contains alcohol.  Alcohol dries out your nasal passages

Take deep breaths in the shower to moisten your breathing passages

Avoid acidic juices like orange juice or any other citrus items

Avoid too much sugar.  It increases mucus production

Avoid dairy products a few hours before recording.  They also increase mucus production