Basic principle: when you are writing your guide, continue to ask yourself "why or why not?" for every point you make. If the only reasons you can come up with are "that's not the way I learned how to do it" or "that's not good form", you need to expand your horizons rather than trying to limit others'.
1. Don't make your guide into a rant about what is wrong with the scene and then try to hide it by stating "this is not the professional way". An example for this: the amount of photographers complaining about young people with entry level cameras shooting for free is just incredible. So there are loads of people who shoot for free, me included sometimes. Deal with it.
2. When talking about equipment, be open minded. I have read the "don't bring a point and shoot camera into the pit" line so many times but I don't understand - why not? If I have credentials to shoot the show, I can shoot with whatever equipment I damn well please. I have some friends who shoot better pictures with their non-professional non-DSLR equipment than many photographers can hope to achieve.
3. Pit etiquette: simple. Smile, be friendly and think about what you are doing. A little consideration goes a long way. However, please don't list all the "bad" things you don't like other people doing. Sometimes, flash is OK! Raising your camera over your head is OK if it doesn't get in someone else's shot! Climbing the rigging is OK if the band and security are cool with it! The list goes on.
4. Remember that the end result is what counts. You can only decide whether a shot is good or not for yourself. You may not like it, but that slightly out of focus shot with a strange crop and 5 standard Lightroom processing filters could be a hit on Facebook. Being bitter about that isn't going to get you anywhere.
Here's a picture I took at a gig just because I can't have a blog post without one. Faces aren't really visible, there isn't a particular focus point, it's heavily processed and there isn't stage context that makes it immediately recognizable. But I like it. So there.