Japanese concerts often involve a lot of audience participation, with many fans complaining about sore muscles after the event, and VOCALOID concerts are no exception. While cheering on your favorite virtual singers can get quite complicated with the hardcore Japanese fans, hopefully this page can teach you some of the basics to get you started.
VOCALOID concerts tend to be a bit glow-stick heavy, with an emphasis on getting the right color for the right song or singer. If you have seen footage of these concerts, you'll notice that pretty much everyone brings glow stick(s) and waves them around. Furthermore, at the beginning of a song, people would switch to the right color, either by swapping glow sticks or adjusting the special color-changing ones. The uniformly colored array of glow sticks in the crowd is evidence of the energy and love for the performer(s). Preparation (making sure beforehand that you will have the right set of colors for the concert) and knowledge (knowing what colors to bring/use) are crucial to achieving this. Hardcore fans attending Japanese concerts are well-trained, memorizing the colors due to experience, so we'll attempt to get you to their level by giving you an overview of the colors.
Furthermore, if you've watched some footage of VOCALOID concerts in Japan, people aren't just randomly waving and jumping around. There's a concerted set of movements going on. While the movements themselves can be picked up, the timing is a bit more tricky. Usually, there's some sort of consensus on the what to do and when to do it built up from a whole series of live events, but sometimes customs are sparked by a few individuals who lead the crowd. Of course, it's up to you to decide how you want to participate in a concert, but we've put up a guide to at least give you an idea of how a lot of the hardcore fans do it. By reading up on the moves and then following song-specific instructions, you can get a sense of how this all works out.