dagny wrote:Charles_F_Bell
This strikes me as a masochist's success. You can get that from Wang Chung here in a "review" that is one-third correct, one-third wrong, and one-third only an opinion. To the ignorant/naive that may look like help.
Charles,
I really didn't see it that way, but as a hint that maybe I should invest in a mystery writing course to see how off base I really am. My ego says the man never read a mystery novel in his life, but my brain tells me that I don't know everything and a little education never hurt anyone. The course I chose is reasonably priced, has a six week duration and will show me what I know and what I don't.
I've gotten really good feed back from this site, Charles. Good editing, good plot advice and reviewers have asked me the tough questions a mystery writer needs to expose holes. I've tried every workshop online and this is the best for getting your work read right away instead of waiting weeks to get your work posted on the main page. So, I'm pretty happy here.
dags 
Wandering off the import of my original comment on the topic, opening lines, you have though made an interesting point about entering into a field of genre writing one may not be immediately competent to pursue. My mind is set on writing what I like and liking what I write, but suppose on a lark, let's say I did decide to write a murder mystery, what be the advice I should follow in the first chapter that you might have learned from the referenced site? For example, I get the sense from reading a few murder mysteries, but mostly having watched movies and TV shows of that genre, the dead body will or will not be introduced quickly within the plot.
Hypothetical first line:
It was a dark and stormy night when Ferd Berfal entered Winterfalls Mansion to find his uncle lying dead in the anteway.
I cannot fathom a logical explanation for rejecting this except to point out that successful murder mystery writer P.D. James does not do that. In fact, she takes a long time before exposing the crime at all. As (an impatient) reader I find that annoying and prefer the Law And Order approach to lay out the crime within the first two minutes. How does an editor draw a line?
If you do not like this example, pick one of your own. Getting past spelling, punctuation, grammar, and basic elements of style, what in particular did you find helpful from the referenced site to write the opening lines of a murder mystery?