In another thread, there was a discussion of the importance of hip and core strength in martial arts. The discussion also involved the importance of squatting to develop that strength. Given that many people here probably do know how to squat with proper form (many who think they do, actually do not) and would like to learn how to squat safely and without pain, I thought it would be a good idea to discuss this issue. Since it is hard to show proper squat form over the Internet, instead, I am attaching a video of one of my favorite coaches teaching form. Admittedly, this video is about learning how to snatch (one of the Olympic lifts), but the first 1/2 of the video is all about learning how to squat and is well worth it for you to watch and practice if you are interested in learning to squat, want to squat with better form, or are experiencing pain when you squat. Dan John is a wonderful teacher and coach who really makes learning quite simple. I highly recommend watching the first 1/2 of this video if you are interested in learning the proper mechanics of the squat. The second 1/2 of this video will be of interest to you if you want to learn the basics of how to perform the snatch (the Olympic lift I am performing in my avatar).
Goblet squats or potato-sack squats are indeed a good way to learn proper squat form. I often teach box squatting or squatting to a low Swiss ball as another way to teach proper squat form since most people squat properly when they learn that it is nothing more than sitting down and standing up (without rocking back to the box or ball take the weight).