Visual Effects is a really broad term that contains a lot of techniques.
I don't have to many visual effects heavy work, but I did this for Absurd Film. They made everything in less then two weeks, from idea, story, filming, editing to finished video. My part were everything 3D like the Volkswagen, Tie Fighter, R2D2, Star Destroyer and more. I had to track the footage to get the camera movements and color match the 3D objects to the scene. I also did the color correction and grading (color mood).