Use correct technique
Lift and lower the weight slowly in a controlled, focused manner. If the weights you’re using are too heavy, you’re only training your ego. Use weights that you can handle so you can target all the fibres in the muscle. If you’re using too much weight (like most people do) you’ll end up doing partial repetitions, and swinging your body all over the place but most importantly of all you’ll put yourself in real danger of getting injured. Reduce your weights and do the exercise properly.