Breathe deeply by using your diaphragm to pull air into your stomach and sides. You should feel your sides expand when breathing correctly.
Practice proper tonguing technique slowly at first, by hitting the place where the roof of your mouth hits your teeth with the tip of your tongue. Play quarter notes at 60 beats per minute and gradually increase to 144 beats per minute as you improve.
Play major and minor scales with a quick articulation by hitting the proper location in your mouth and then quickly retracting the tongue. Start by playing your scales at 60 beats per minute in 16th notes, then gradually increase your tonguing speed to 120 beats per minute.