How can I make my voice clearer?

Vocal hygiene. If your voice is raspy or chronically hoarse, go see your ENT for evaluation. Common problems which can and will damage a voice include cigarette smoking, acid reflux disease, vocal abuse (excessive shouting, singing, humming), and more. Voice therapy may help as well. Based on your voice and your exam, your ent/laryngologist can help recommend the best treatments. Best wishes...
Train it! The voice is a precision instrument that too many people take for granted. If you haven't already taken them, consider formal voice lessons from a singing teacher with a good reputation in your area. You may also simply need voice rehabilitation. Get your voice checked out by a doctor who treats problems of the voice.