1) Wash your hands before touching food.
2) Cover your fucking mouth when you cough or sneeze, and wash your hands.
3) If your nose is runny, or you have something in your nose, use a tissue to blow your nose, dispose of the tissue in the trash, and wash your hands.
4) Bathe every day.
5) Never wear the same clothes twice.
Too bad most people are too stupid to practice proper hygene, despite countless reminders, campaigns, and instructions.