Work on your posture. Keep your chin level, be careful not to clench your jaw and keep your shoulders flat. Do not hunch your shoulders.
Practice exercises to relax your throat muscles. Lower your chin to your chest and raise it toward the left shoulder. Move it back to the center while staring straight ahead. Shift your head to your right shoulder, then point the chin toward the shoulder. Roll the head back to the first position, then do it in reverse.
Breathe with your diaphragm to stop strain on the vocal cords. Breathe in with your stomach instead of your chest to help the vocal cords open correctly. Keep your back straight when breathing and watch yourself in the mirror. Your stomach should rise and fall and not your chest. Lay flat on your back and place your hands or a book on your stomach. Practice breathing so your hands or the book rises and falls.
Warm up before singing to prevent your vocal cords from becoming tense.
Focus on your breath. Take long, deep breaths to relax your body.
Pant. People with vocal cord dysfunction can benefit from practicing panting. It lets the vocal cords relax and helps breathing by increasing the glottic aperture.