In order to make a proper change to your golf swing, there must first be an analysis. When a swing is analyzed, positive and negative aspects are pointed out. There are also cause-and-effect relationships discussed. A swing analysis can be done with the naked eye, mirror, or video and computer technology.
Video analysis has become the norm for most golf academies and top teachers. Video will give the student a visual idea, and a clearer understanding of the lesson. Modern swing analysis programs allow the teacher to slow down the swing into still frames and use computer-generated graphics to analyze.
The most modern form of golf swing analysis uses 3-D images and calculates specific angles and speeds of the body and club. A particular putting system uses ultrasound to measure the putter's motion; full swing systems use motion sensors and reflective markers to measure the body motion.
When viewing a swing with video or in the mirror, the best viewpoints are from "square angles." To view body motion, the best angle is from face on. The best angle to view the club face angle and swing plane is from the "down the line" angle, looking down the ball to target line, or the shoulder line.
A big part of any type of swing analysis is presenting the preferable motion or technique. A golf lesson will start with an analysis of the student's current swing, then there may be an analysis on a desired model swing, a previous swing from the student or a demonstration from the teacher.