Are there rules that should always be followed when you are writing?

Lately, I have seen lots of recommendations for what makes a great opening paragraph, what key things should you always have in your first chapter, what makes the perfect ending to your story, is your story speaking to your target audience, etc.  I have the greatest respect for these points and mean no disrespect in making reference to these suggestions.  I have no claim as an expert in the area of writing, and there are plenty of more experienced people out there to give comments.  I just...