If cough is severe along with breathlessness or wheezing or dullness and refusal to feed,consult your paediatrician asap for physical examination and investigation for further management. If mild,just give steam inhalations for cold and cough and decongestant nasal drops for nasal block or increased cough on lying down. Use paracetamol for fever and repeat every 4 hours if required. If not improving OR accompanied by other symptoms like vomiting or loose motions or breathlessness or wheezing and refusal to feed,rush to your paediatrician.