Cross-Posting & other forum issues

I posted this on another board and didn't get any response, so I will now risk the very subject I am asking about!! How ironic!

I see occasional apologies for cross-posting. Also similar posts on more than one board with no apology. What exactly are the guidelines for such?
Has anyone compiled a guide for newbies on proper forum behavior?
Sure, some wouldn't care, but a lot would so they don't ruin their credibility before they get started.
Seems like there should be a better way for newbies to learn proper "form", than to either watch others be flamed/corrected or make fools of themselves (and get flamed/corrected personally) or lurk for months trying to read between the lines. Maybe even having their first posts zapped without realizing why.
Could this possibly be an idea for a product to sell? If so feel free to kick some royalties my way for stimulating your brain!! Just kidding! (sort of)
I'd produce it myself, but as you can see from my first question it might be a little shy on good content. LOL
Just wondering, Dave