Many people have bad breath without even realizing it. This can cripple your likelihood of enjoying a healthy social life, finding a significant other, and even advancement in your career. Halitosis or bad breath is mostly a result of poor hygiene and is completely treatable. It is quite easy to prevent and fix bad breath with the following guidelines.

Brush your teeth and scrape your tongue first thing every morning, and also after each time you take a nap. Foul-smelling bacteria have had a chance to take over your mouth while you slept, and are most likely causing yucky "morning breath." Tongue scrapers can be found in most health food stores, and also in drug stores and convenience stores as they become more popular.
After you brush your teeth and scrape your tongue, rinse your mouth thoroughly and gargle with fresh, cool water. This is a very important step, one that many people overlook. Nobody likes to smell your breath when it's laden with dirty, used toothpaste scum.
Drink plenty of water - Insuring that you drink plenty of water throughout the day can help to control bad breath (halitosis). This can be an especially important consideration for those people who suffer from xerostomia (chronically dry mouths).

If you allow yourself to become dehydrated your body will try to conserve moisture by reducing its production of saliva. Saliva has a cleansing and diluting effect on the bacteria and bacterial waste products that cause bad breath. A reduction in the amount of saliva in your mouth can make it harder for you to control odors associated with your breath.
Rinse your mouth with water often - Rinsing with water can mitigate bad breath problems for brief periods of time. Rinsing will both dilute and partially remove the bacterial waste products that are the cause of breath odors.

Stimulate your mouth's flow of saliva - You can help to minimize bad breath odors by stimulating your body's flow of saliva. This is because saliva has a cleansing and diluting effect on the bacteria and bacterial waste products that cause bad breath.

One way to stimulate salivary flow is to chew on something. Doing so will trick your body in to thinking that it is getting a meal. And in preparation for digesting this meal your body will increase its production of saliva.

Chewing gum, cloves, breath mints, or lozenges can also be used to stimulate salivary flow. If you elect to use one of these products make sure it is sugar-free since sweets will promote the growth of bacteria that cause tooth decay.
After you eat or drink anything (besides water), thoroughly rinse your mouth and gargle with water. Use this practice without fail, day and night, and you will keep abreast of nasty bacteria buildup in your mouth, which cause bad breath. Run your tongue along the surfaces of your teeth throughout the day, and if you ever notice any plaque buildup, brush your teeth again and rinse thoroughly with water, making sure that you feel your teeth, not plaque buildup, which is a contributing factor in bad breath.

Fixing Bad Breath on the Spot -

Drink water and ask for lemon to be included. Surreptitiously squeeze as much of the lemon into the water as possible, as it will help cover up the odor.
Chew a piece of gum or eat some mint candy.
Gargle with salt to neutralise some of the odour.
Sneak a spoon into the bathroom. Check to make sure you're alone. Look into the mirror, stick out your tongue and check for a pasty white goo on it. Turn the spoon upside down and use it to scrape your tongue, using a back to front motion. If you can't manage to sneak off with a spoon, head to the restroom, wash your hands, use your fingernails to scrape your tongue.