Swordsmith's right that you're mostly on your own as far as book promotion goes when your first getting started, though I'd like to say that my WebMage publicist at ACE, Maggie Kao, has been fabulous and very responsive. I will also note that there are definitely some self-promotion things that are worth doing. But in general I think most self-promotion is a bad use of a writer's time. And that's for three main reasons.
First, if you're a good enough writer to get something published, you're almost certainly a pretty damn good writer. This is for the simple reasons that the odds of success are lousy. That means you've got a highly specialized skill set for writing. So, one of the first things you have to ask yourself is: do you also have the skills for promotion? If not, you're almost certainly better off investing the time and effort you'd spend on promotion in making your next book irresistible.
Second, with the print numbers of a typical big press book there's really not a whole lot the author can do to make a significant dent in sales. Sure you can maybe move a few hundred copies by investing hours and hours in promotion, but a few hundred copies doesn't really matter that much when the print run is 40,000 and no matter what your personal production level, those hours are valuable.
Third, if you do move ten thousand copies of your first book by your efforts alone, you've put yourself in a dangerous box. With the way sales are tracked now the last thing in the world that you want is to have your sales numbers moving down from book to book, and that means that with your second book you then have to move more than that ten thousand copies by your own efforts, and more still with each successive release. And, unless you can work some kind of magic, that means you have to put more and more effort into promotion with each release and that leaves you less and less time for writing, which is presumably why you started out doing this in the first place.
My basic rules for promotion are that it should involve no money, no time, and no effort. I'm willing to bend the rules a little for pure promotion's sake, but not much. Some time, a little effort, a couple of bucks.
I will also bend them for things that I enjoy doing, like cons, readings, and interviews. I'm a social person and an escapee from the theater asylum. I like meeting new people and being out on stage. I would do these things even if I wasn't writing, though the book sure helps get interviews. But that's me.
If you're a writer who doesn't like those things, or if you're not good at them, don't feel guilty about keeping it to a minimum. Even if you do enjoy them, realize that it's a trade off. Time spent on promotion is time spent not writing.
I would never say that a writer shouldn't do any promotion, just that you have to be very careful about how much and in what way. As I said, I do signings, though not many, and readings, and a few conventions. And all of those things are more important for someone who is just getting started than an old pro.
One other thing I do and I would urge any writer to do is I stop whenever I'm passing a book store that's likely to have my stuff so I can make connections with the clerks and offer to sign stock. Likewise when I'm traveling which I do a fair bit for other reasons, I make sure to locate and visit book stores in the area.
All that said, there are, of course, going to be exceptions to this rule, instances where self-promotion made the difference in someone's career, but it's something to think about very carefully.
Thoughts? Rants? Praise?