Summarize the following:
Set your feet a little wider than shoulder-width apart, with one slightly in front of the other. Moshing along with an unruly crowd can send your body reeling. By staggering your stance, you'll be ready for unexpected changes in direction. For maximum composure, stay poised on the balls of your feet. The lower your center of gravity, the more sturdy your base. Not only will this help you keep your balance, it will also absorb some of the force created by flinging your head, neck, and shoulders around like an electrified wildebeest that's had too much caffeine. A solid foundation will also keep you from getting run over in an out-of-control pit. Stand your ground! As the band launches into their first number, raise and lower your chin a few inches to follow along with the beat. Try to let the tempo of the music guide you as much as possible, unless it's a real ripper—you don't want to go too hard too soon.  This is the “warm up” phase of the show. The real headbanging will begin a few songs into the set once everybody cuts loose. The head nod is a good move to go back to if you start to get tired or dizzy. During the song's main guitar line or chorus, start swinging your head in longer and more exaggerated motions. Lean all the way down to about waist height before coming back up. This is a more slowed-down style of headbanging that emphasizes the heaviness of the music.  It may help to headbang along to the bass line if the drum beat is too fast to keep up with. Watch out for the person in front of you to avoid knockin' noggins while you're getting radical. When the band turns up the aggression level, or unleashes a particularly savage solo, bend over at the waist and rapidly shake your head up and down. This technique is sometimes referred to as the “whiplash.” The key here is to use small movements so you can go faster—you only want to lift your head a few inches at a time.  Headbanging at this velocity can quickly leave you exhausted and disoriented, so be sure to take a few moments to rest between songs.  High-speed headbanging is most often performed at death metal, thrash, crust, and hardcore punk shows. It may look out of place at a doom, sludge, or industrial set.

Summary:
Assume a comfortable, stable stance. Keep a slight bend in your knees. Start with a slow, rhythmic nod. Slam hard to the heavy riffs. Speed up to match the tempo of a breakdown.