What arises partly from backstory

This is not advice. It's just what I do. Take it or leave it.

Most important (learned the hard way) or the only advice you need

Do not try to construct, create, write or craft a play based on what you read here or in any other How To text. First write the play then check the How To books and sites for pointers on how you might make the play better (that is if you believe it could be better). So if you do not have a first draft in front of you right now, close this site and finish the first draft. 'Bye.

Still not convinced? If you ignore this advice and plunge ahead on a first draft with crocks of advice from all and sundry on how to do it you will end up with what looks like wads of jigsaw puzzle pieces forced together with a hammer and revealing... nothing. I have drawers full of hammered jigsaws. The only things I have written that work are ones that I wrote straight out with zero input from How To'ers. Those where I stopped to check what so-snd-so has to say about such-and-such (and blindly followed the advice) failed. So, finish the first draft, let it sit, rewrite it once to tighten it up or repair some broken mechanics. Then check the How to advice and apply it with caution.