Start with breathing exercises. Take slow, deep breaths that use all of your lungs and force the diaphragm to control the amount of breath exhaled. This is the correct breathing method for singing.
Keep a good posture. This includes keeping your head up, chin level, knees loose, shoulders sloping, muscles relaxed and body weight on the heels and soles of your feet.
Stretch your mouth muscles by mouthing the five vowel sounds without singing.
Recite tongue twisters. Start them off slowly and build up to loosen your tongue and vocal chords.
Sing short one-syllable notes repeatedly such as "ha" and "ho" (called staccato notes). Remember to project from the diaphragm and not force the breaths out. This is what you should focus on in these voice exercises.
Sing one note and hold it as long as you can to determine how long you can hold a note in one breath. Also, build the note's scale up and down (called singing an arpeggio) to get a feel for every pitch.
Recite notes that focus on the vowel sounds as well as the doh, ray, me, fah, so, la, te, doh scale. Change the vowel or consonant sounds every two or three times.