Learn the difference between the soft and hard palate. The front part of the roof of your mouth, where it feels hard, is the hard palate. The soft palate is toward the back of the throat right before the epiglottis. Direct your air toward the hard palate and avoid using the soft palate to sing as much as possible.
Breathe properly. Take air into your stomach by expanding the muscles of the diaphragm. Then, when you expel air, use the diaphragm to control the airflow. Aim for a steady and moderate airstream. The goal is to keep the vocal folds vibrating at an even and controlled tempo.
Avoid thrusting your jaw forward. This will create tension in your throat and create a nasal sound. Keep your jaw relaxed and slightly back.
Stand with proper posture. Keep your neck straight and relaxed, your head high, your shoulders slightly back and your legs about shoulder-length apart. This will remove tension in your body, lowering the amount of tension in your throat and decreasing nasality.
Relax the tongue when singing. Avoid bunching the tongue toward the back of your throat, as this will limit the airflow and create a nasal sound.