In this video from lkobet1 we learn how to curve a soccer ball. It is very useful for free kicks and set pieces. First you need to focus on getting a good position on the ball. Set up the ball on a really good piece of grass. Put your foot where you will land to kick it. Take a few steps back. Kick the ball with the side of your foot, not your instep. Come through the ball and across your body. That's the key to curving it. Coming through the ball when you kick with your leg will make the ball curve.