I thought it might be useful to mention (and link to) some blog posts and sound advice which I followed as I edited and prepared the ms for mailing. Firstly, this excellent post by Elizabeth Craig on Keeping it interesting, which helped me to focus on those moments when the story might be slacking off, helping me to keep it fresh and the reader engaged. Dmytry Karpov's blog post, Brevity is key, was a good reminder of one aspect in the editing process: getting rid of anything unnecessary. Finally, as I was about to send it off, I came across this insight by Rachelle Gardner, into what might be going through an agent's mind when she reads my ms.
All of the above, by the way, I discovered via Twitter. I wholeheartedly retract my earlier peevishness about the value of this brand of social networking; it's a goldmine. Of course, you all knew that already, but it took me a while to get past my Luddite objections and see for myself. I'm very glad I did. If you have a Twitter for me to follow - your own or a recommendation - please let me know.