How to cure fever?

Depends: Fever is a symptom, not a disease by itself. The cause of fever needs to be determined and treated. It would be prudent to see a doctor.

Fever: Fever is usually a symptom of infection. If you think you just have a mild illness like the common cold or a simple viral cough then it is probably safe treat the symptoms and see how you go. Medicines like paracetamol and ibuprofen can be effective at lowering your temperature which may make you feel better but won't make you get better faster. Remember to drink plenty of water and rest!

Fever: This is your body's physiologic response to some, generally inflammatory process, which resets the internal thermostat so as to allow you to increase the temperature. This is a symptom, not something you can cure by itself. If you can find the source of the fever-inducing stimulus that may be treatable.