I've been reading a chapter about what happens after you get a book published from an inspirational book Chapter After Chapter by Heather Sellers. Heather is a very nice author (I've met her on several occasions) and has some great, down to earth advice about what to expect.
Heather of course advises planning to make time for readings, workshops, lecture and interviews, but she also advises that "this kind of basic publicity is not, as is commonly thought, the job obligation of the publisher, your editor, or their publicity team. It's your book. It's your job."
Wow. It's tough to hear it in those terms (especially, when as a marketer I like to think I do as much as I can for the authors I work with), but Heather is right. Hopefully your publisher has a marketing and publicity team that will do what they can to promote the book in it's early stages, but a lot of the book's success will depend on your own promotional efforts. Being realistic about how much effort you'll need to do on your own can make a big difference in the experience you have marketing your book. If you expect your publisher to fly you around the country for book signings, you're bound to be disappointed. On the other hand, if you work with your publisher and communicate with them about the efforts you are putting forth on your own, they are more likely to try to help out any way they can.
Check out Heather's book... it's full of great writing advice and will help you stay excited about the craft.
Also visit her website: www.heathersellers.com