It curls. I only started scoring freekicks yesterday. So far I can only score them in the range of 17-25m.
17-23m: I hold down to lessen the power and make sure your power doesn't exceed the half way mark on the power metre. Most times when I get it on the mark it goes in or the keeper saves. But the most important thing is holding down and of course the curl. That's what changed for me. As soon as I started doing this, my freekicks are almost guaranteed goals.
Hold down as the power metre is being filled and then when you have your power set and the player kicks the ball, hold the direction in which you want the ball to curl
23m+ : I don't hold either up or down. Holding up will send it over or blast it into the wall. Holding down is just too weak. Keeper will always get it.
Note: For more accuracy, the power must not exceed the half way mark of the power bar. Try as much as you can to get it spot on the mark. Train, train, train.