To strengthen your chest voice, you need to practice regularly and use proper technique. Before singing in chest voice, warm up your voice with gentle and gradual exercises like lip trills, sirens, or humming. Then, sing scales or melodies in chest voice, starting from a comfortable pitch and gradually expanding your range. Use a metronome or a piano to keep track of your pitch and tempo. Additionally, sing along with songs that use chest voice like "I Will Survive" by Gloria Gaynor, "Livin' on a Prayer" by Bon Jovi, or "Rolling in the Deep" by Adele. To ensure proper technique, use breath support and posture while singing in chest voice. Breathe deeply from your diaphragm, keep your shoulders relaxed, and align your head and neck with your spine. Avoid raising your chin or tensing your throat when singing high notes in chest voice. Lastly, balance your chest voice with your other vocal registers and modes. Don't sing in chest voice all the time, as this can cause fatigue and damage to your vocal cords. Learn how to mix your chest and head voice to create a smooth transition and a versatile sound.