I think the first thing for me was waiting...sometimes I get so impatient. The next challenge for me was editing my book before sending it out. The more I read through, the more I made changes here and there, I almost drove myself crazy until finally I gave up! In the end it was 2 lessons well learned.
Fortunately, I knew what to expect in terms of the marketing and promotions of my books. However, as I speak with various writers and authors they also didn't realize the work it was going to take to get their book the exposure it deserves.