What can i do to treat this cough?

Acute or chronic?: Chronic is either from chronic bronchitis from smoking, gastric reflux, cough variant asthma, post nasal drip, etc. Therefore the underlying condition needs to be identified and treated. Acute cough often responds to honey, dextromethorphin , hydration, narcotic based cough preparations, lozenges, and humidity.

Depends on the cause: Cough is a symptom--why do you have it? If it's been there for less than three weeks and you have no other symptoms (short of breath, blood, wheezing, fever, feel really ill) it's probably a cold and you can wait it out. Common minor causes of prolonged cough are hay fever, heartburn/acid reflux, and asthma. But it can also be caused by infections and many other illnesses. See a doctor.

Diagnose first...: If this is an acute cough, it is probably due to acute bronchitis caused by either a viral or bacterial infection. A viral infection will run its course but a bacterial infection may require antibiotic therapy. Your doctor can diagnose and treat this. If the cough is chronic, etiologies include bronchospasm from any cause including chronic bronchitis, a form of copd, gerd, post-nasal drip. See doc.