Writing a novel is just half the job

Hello everyone. What is the hardest part of the book process? Writing your book, publishing your book, or selling your book?
I have been thinking about this quite a bit lately. It took me 3 months to write the first complete draft of my novel Black Numbers. It then took me another year of rewrites and edits before I started sending out submissions to literary agents and publishers.
Because it is so difficult for new authors to break in to the traditional publishing arena, I decided to self-publish Black Numbers and have it sold as an eBook on Amazon, Apple, Barnes and Noble, Sony, Diesel, Kobo, and now the Android/Apple App stores.
I thought, hey, now I can sit back because my job is done.
Unfortunately, after reading some great articles and talking to some great authors, I quickly realized that my job had really just begun.
Marketing one's book is just as important as writing and publishing it. So I created an author Facebook page, joined a half-dozen author/reader FB groups, created a Twitter account "@DeanLappi", and began getting to know other authors. I have to say that getting to know other authors is my favorite aspect of marketing my book, as they are fantastic people who are going through the same process. I learned a lot, and my hats off to them.
Twitter has been great too. I had never been on Twitter until a few weeks ago, not really understanding the need for it. But upon some great advice from author Michael R. Hicks, I jumped into that social media and I haven't been dissapointed. I've met some great people, gotten my book out to a new group of readers, and received some great advice from other authors.
So that is my journey over the past few weeks. It is just the beginning, but I am happy with my start. I will post more as this journey continues.

Cheers, Dean