My voice is hoarse sometimes. What can I do to cure this?

Depends. To treat the hoarseness, one needs to know the cause. An otolaryngologist (ENT) doctor would be in a good position to provide evaluation and treatment with the goal of improving or possibly curing the hoarseness.
Depends. This can be from many causes. It could be vocal hygeine, acid reflux, nasal drainage. The best way to be checked is to see your local ENT who can perform endoscopy and evaluate your vocal cords.