Improve your posture. Stand upright or sit with your back straight. Balance your head evenly on your neck.
Warm up your voice. Go through your entire vocal range. Open your throat all the way. Sing without tension in your throat. Feel the notes through your nasal membrane and feel it in your jaw and tongue. Relax your throat and head and neck muscles.
Listen to the music closely. Pay particular attention to acoustic instruments. Avoid listening to the bass line to find your pitch.
Aim your voice directly at the pitch. Sing with the purpose of hitting a specific note.
Practice singing your vocals perfectly. By focusing on hitting the correct notes consistently you will train your ear to avoid pitchiness.