There are several techniques for taking freekicks but it basically depends on the person taking it. You need a high shot power level to get power behind it. But more importantly, you need freekick accuracy (obviously lol) and swerve. Swerve is very important and when your shot actually goes in it looks brilliant and professional.
Take Cristiano Ronaldo for example. Once he develops he becomes very good at freekicks, high freekick accuracy, swerve and power. Rooney has the same too.
I tend to try and get the power bar up to half way, or as close as possible for a controlled shot.
Try holding R2 when taking the freekick. This makes it dip but it usually hits the wall for me. Try it from a further distance, 27m for example.