Simple tongue twisters help to train the lips, tongue and teeth to move in careful coordination with each other. Practice saying "how can a clam cram in a clean cream can" over and over again. Be precise, and start over if you make a mistake. Concentrate on precision at first and only pick up speed when you can do so without making mistakes. Also try, "the big black bug bled blue blood on the big black barn" and repeating the phrases "Peggy Babcock" and "Toy Boats" over and over again.
Learn to simultaneously relax the jaw while increasing control of the muscles that move it. Relax the jaw by yawning repeatedly during your speech work. Open your mouth increasingly wide with each repetition. Don't force it open, but concentrate on relaxing the muscles so it drops further open naturally. Refine control with the jaw by taking a piece of text and reading it aloud. With every move that requires you to open your mouth, exaggerate it and open the mouth as wide as you can. Slowly read your way through the text with precision.
To limber up your tongue and make it into a more precise instrument, use it to rub each of the teeth in your mouth. Reach backwards with your tongue and find each tooth individually. Run your tongue gently in circles on the surface of the tooth and then move on to the next one, carefully doing each tooth in your mouth. Then, alternate between opening your mouth wide and stretching your tongue to the floor and trying to touch your nose with your tongue.
This exercise is good for the lips, tongue and jaw and helps to bring the other techniques together. Place a cork firmly between your upper and lower rows of teeth. Find a piece of text. Without dropping the cork, carefully read your way through the text. Take care to ensure that you are as clear as possible and that you make no errors.