One possible note in defense of the four-novels guy: I've got two novels out there right now, and another one that'll be out by the end of the year (likely to WotC). Here's how the submission process has gone:
Book One (Victorian Fantasy Novel with Mystery Plot):
12/2001 -- Out to Tor
10/2002 -- Queried Tor
04/2003 -- Queried Tor again
08/2003 -- Queried Tor again
10/2003 -- Sent a "Please respond to my query, or I'm withdrawing" letter.
10/2003 -- Withdrew and sent to Daw
It has been at Daw for more than a year now. It's still there, because they politely answered my query and said, "Sorry, it's taking a long time." Tor, however, never responded to any of my queries, which I sent by letter and by e-mail.
Book Two (Modern Tongue-in-Cheek Epic Fantasy) has been at Tor since 11/2003. I'm not even bothering to query on that one until a year has gone by. And even then, I dunno. I might withdraw after a year and a half. I might let it sit awhile longer.
Book Three (Swashbuckling Fantasy Romantic Comedy) will go out by the end of this year. It'll either go to Baen (the only other major publisher I know of that's taking unsolicited and unageted submissions right now, and which has a turnaround time of about two years, reliably) or to WotC. Haven't decided which, to be honest.
Book Four (rough description: If "Ocean's Eleven" were a fantasy novel) gets started as soon as possible, and likely goes out near the end of next year, after the rough draft, set-aside period, crits, and rewrites.
So I'd easily buy four novels being out there, even if it's a good author. I'm not saying I'm writing bestsellers, but my geek-buddies read a lot of stuff, and they say it's better than a lot of stuff they've paid money for. Breaking into the novel market sans agent isn't necessarily difficult, but it's nigh-impossible to do quickly. There are about four pro-level markets out there that take unagented submissions (Tor, Daw, Baen, and one I'm forgetting, not counting WotC), and they all have slush-turnaround times of a year or two. If you get a response earlier than that, chances are that it's a form rejection letter.
(Of course, four unpublished novels doesn't mean that you're automatically a good author -- it just doesn't automatically mean you're a bad one.)
As far as other general writing advice goes, I figure that at this point, anyone writing specifically for this open call should just do the best they can. Any advice that anyone gives here at this point can be misread, argued with, or reductio'd ad absurdem, and the number of people who are going to make meaningful improvement because somebody here said, "Research", "Outline your plot", or "Don't have your heroine meet Legolas, Neo, and Commander Data and have all three of them fall in love with her and fight over her until she cries and runs away in order to stop them from killing each other, only to perish at the hands of bad guys, so that Legolas and Neo can then cry over her and Data can say something about feeling an odd sense of loss, which might be considered grief," is pretty tiny.
Write the kind of story you'd want to read. Anything else is either going to go over your head or result in you getting defensive and pointing out examples of famous people who did what someone just said not to do and got published anyway.