1. Start tweeting. I do have a Twitter account for my music news, but I hadn't set up an author one until after the book was out. This was a lost opportunity because Twitter is a great way to connect with people and both send and find out information instantly.
2. Blog about writing. Ditto above. I've been writing for years, and if I'd had a blog, I wouldn't be working from the ground up right now trying to find a niche.
3. Send out ARCs. I had no idea what advanced review copies (ARCs) were until long after I released my book. Turns out there are a TON of book bloggers who love spreading the word about books, but who often have a backlog of 1-3 months. Sending a copy early ensures a review can come out closer to the release date, building buzz. I'll try to do this with my next novel, rather than have reviews trickle in.
4. Learn more about promotion. I have a shelf full of books and magazines about writing and all of them are outdated. The new methods of promotion are changing faster than people can write books about them. And sure, ebooks about the subject are helpful, but sometimes I find out more about promotion just by watching Twitter streams like #writechat.
5. Set my goals higher. When I released my book, my goals were very modest--eighteen sales. After I hit that I was wondering where to go from there. Hopefully over the next few months I can iron out better plans for my next novel, so it can reach more people who would enjoy it.