Wet your lips slightly
Relax your jaw
Make a small round opening with your lips
Place your tongue back and slightly curled
Blow a steady stream of air
Adjust lip shape until the whistle is clear
Increase air pressure gradually
Practice different tongue positions
Keep your mouth muscles firm but not tense
Try whistling with fingers if needed
Use a sharp, focused breath rather than a wide blow
Repeat until you find the loudest pitch