Good evening everyone! Girls, could you please tell me if my daughter…

Good evening everyone! Girls, could you please tell me if my daughter started coughing frequently in the evening today. She began coughing at night, like a full nose with coughs, but there's no actual cough. How can we prevent colds in their early stages? Should I feed her more often? She had been ill three months ago, then she also coughed and had phlegm. Last time the pediatrician prescribed an inhalation. Thank you in advance for your answer ?