Chew With Your Mouth Closed

Chewing with your mouth closed is good ettiquette as you grow up. Sometimes, it is hard to remember to chew with your mouth closed. You might also need some practice.
Practice first with gum. Close your mouth and chew with your back teeth. Use one or two sticks of gum first to practice.
Start out with small portions of food, first liquidy food like ice-cream or yogurt. Put a little bit of the food into your mouth. Now close your mouth, chewing with only your back teeth. Chew slowly, this helps you to close your mouth.
Once you have mastered it with the soft foods, try larger portions into your mouth at a time, like you would normally eat. This is no reason to open your mouth. Still chew with it closed.
Start out with the harder foods now, like fruits and rice and bread. Follow the same principle: small portions at first, then slowly worrk your way up. Chew slowly.
Once you are past this stage, try the hardest foods like granola bars and cereals. While these may make noise, it is no excuse to open your mouth while chewing.

Reward yourself for every day you chew with your mouth closed. It will help you and encourage you.
Ask someone to monitor you.
If you are having trouble, look at others chewing with open mouths and make yourself think that it is insanitary.

Never offend others with this; it may hurt their feeling