How to keep your voice clear

1 Stay hydrated. If you have a lot of mucus in your throat, hydration can help. Liquid can help soften mucus, making it easier to expel from the body. Try to drink about eight glasses of water daily. If you're struggling with a sore throat, you may want to increase your water intake slightly. Seltzer water may help with a scratchy throat.
2 Try to stay away from fruit juices and soda. The added sugar can cause additional throat irritation. If you want something other than water to drink, go for sports drinks or fresh squeezed juices that use only natural sugar.
3 Try to stay away from fruit juices and soda. The added sugar can cause additional throat irritation. If you want something other than water to drink, go for sports drinks or fresh squeezed juices that use only natural sugar.
4 There is a belief that milk and dairy products increase phlegm production, but there is no scientific evidence that this is true. They may cause the phlegm to be thicker and more irritating to your throat, but frozen dairy products can also be soothing and a good source of calories when you may not be eating because it is difficult to swallow.
5 Try honey and lemon. Honey and lemon both help soothe the throat. Try adding a squeeze of lemon juice and a teaspoon to a glass of ice water or tea. Not only can this help clear phlegm, it may also ease any pain or irritation you are experiencing.
6 Drink green tea. Some people find green tea help soothe the throat. Try adding honey or lemon to green tea for added effect.
7 Choose healthy foods for your voice. Certain foods are good for the voice and help promote a clear throat. Whole grains, fruit, and vegetables contain vitamins A, E, and C which help keep the throat free of mucus. If you have a sore or strained throat, try eating softer foods until the irritation clears.
8 Do not clear your throat too often. Coughing, wheezing, and otherwise attempting to clear your throat can sometimes provide momentary relief. However, if you engage in these behaviors too frequently when you have a sore throat this can cause irritation. This could potentially increase the duration of symptoms.
source - wikihow