Summarize this article:

With every beat of the music, you'll pop a shoulder. "Pop" here meaning move it up and out to the side quickly. The rest of your body should sort of flow with each pop -- it's not only your shoulders that are moving. You're sort of moving your shoulders in arch, starting from the inside and going out. When you pop your left shoulder, your right hip should jut out. The hips should follow behind the shoulder by just a split second. If you're popping your left shoulder first, go left, right, left. Then pop right, left, right. If you're working with music that's 4/4, you'll be using the half-beats, or the and of 1 and 2 (for example). Start going faster and faster. Electronic dance music can be really, really, fast and keeping time is absolutely imperative. When you pop your shoulders, your arms should be bent at the elbows, with your forearms and hands going toward the other direction. So when you pop left, through your arms right. When you pop right, throw your arms left. Keep your hands in a loose fist. When you pop a shoulder, it moves up a bit. To exaggerate this, move the other shoulder down a bit. When you add in your arms, this looks especially good and loosens you up. Your arms will then be at slightly different levels. Keeping the same basics (popping shoulders and opposite arms), get creative. Move your arms to shoulder level or even above your head. Add in a hand movement on the beats (dirt off your shoulder, maybe?) to jazz it up. It's still the Harlem Shake! When you're working with music that's 4/4 (as most music is), alternate between working in threes (hitting pop, pop, pop on 1 and 2, 3 and 4), and working in twos (hitting pop, pop on 5, 6). So you might pop your shoulders five times on 1, and, 2, 3, 4 and then five more times on 5, and, 6, 7, 8. The Harlem Shake is a dance move that goes back to the 80s -- it's not just some recent YouTube phenomenon, despite what your friends may tell you. The video craze just involves dancing wildly and has nothing to do with this dance move. However, if you want to get creative, do the Harlem Shake while you're making a Harlem Shake video. Only a few people will understand what you're doing, but they'll appreciate it!

Summary:
Alternate popping shoulders, left and right. Do it in threes. Start using your arms. Add personality to it. Know that this is different than the video craze.