I've just finished judging entries for a local contest. I've learned an amazing amount. Much of it encouraging to all us creative folks who struggle with rejection.
First, the work matters. It's easy to spot a beginning writer. It's easy to spot a writer who's worked on the craft and written some. It's easy to spot a writer who's written a great deal and who has learned many lessons from writing all those words. (Talent doesn't seem to enter into it--but that's for another post.)
Second, I've gained an understanding of not only what agents go through, but that the agents tell the truth when they say "Sorry--just not my type of thing." The best entry I judged was excellent, compelling and professionally written at a high, high level. But if I had been an agent, I would not have taken this writer as a client. Why? Not my type of thing. And as an agent, it needs to be "my type of thing" for me to know who, how and where to sell the manuscript.
And a final note, somewhat related: I've had a manuscript out, making the rounds. In my research of agents, I've come across some great agent blogs: Nathan Bransford, Lyons Literary LLC and Bookends, LLC to name a few. These blogs give great information and advice on finding an agent and the publishing world.