Here's a real mark of the amateur-- when you're not using the perfectly sensible, accessible, and learnable techniques that help a reader know what you mean, like names instead of pronouns or recasting the sentence to identify who is thinking, acting, speaking; punctuation and paragraphing to make it clear what's happening. You have to go beyond what you know in your head (you do know who is saying what) to see what you've put on the page, and how to revise to make this understandable to the reader.
This is an adaptation of an actual submission (I changed everything but the structural issues):
Hal said, "I've always wondered. Have you forgiven yourself yet?” He shook his head. How could he forgive himself? His parents had lost their life savings because of him. He'd gotten caught up in the adrenaline rush of starting a new company, and they were his parents, and they wanted to support his efforts. And he wanted them to be proud of him, the first in the family to make something of himself. “How much was it?”
He turned abruptly to face his tormenter.
“The bankruptcy court hasn't figured it out yet.”“And you never wanted to ask them what it cost.” As Hal touched his arm, he felt the sympathy. But one person forgiving him—everyone forgiving him—wasn't going to make it right.
(And it goes on like that-- Hal speaks, "he" reacts/thinks/acts in same paragraph, and it's all very jumbled.)
When I read a passage like that, I figure I'm not dealing with an accomplished writer, because this writer has no understanding of what is happening in the passage, what the reader will be experiencing while reading.
(And yes, of course you can go beyond the conventions of paragraphing and punctuation... if you know what you want to accomplish and know when you've accomplished it and when you haven't. I'm all for that... but I also think if you do it well, the editor or agent will probably understand what you're doing. :)
This is especially important in that first couple paragraphs. There's a real tendency to want to shove too much into the first paragraph, and often this is shown in very long complicated sentences. (More accomplished writers tend to the other extreme-- they are often so cryptic that I can get a page into the story without knowing what's going on.) But as you know, if you lose an editor on the first page, you've lost her forever. You don't need to be clever or innovative in those first paragraphs-- clarity matters most. (That doesn't mean that you have to tell all, or that the reader has to know everything-- but the reader should know what you want her to know, and be intrigued enough to keep reading.)
Anyway, another in the long-running "mark of the amateur" series. But you guys aren't doing that stuff! So often I think I'm preaching to the choir. (At least you don't make me blow on a pitch-pipe!)