Writing "The End" on the last page of your novel really translates into the beginning of taking yourself serious as public persona, becoming a salesperson, learning about marketing, showing up as presenter, or speaker, a writing instructor, and the list goes on until we run out of clever ideas. Our work plus editing process can, and will, sometime take years (my novel Clinging to Deceit took almost 2 1/2 years before it was published) but it all doesn't end there.
I heard an author say during a well attended author panel event that she wasn't selling her own books or that she wasn't going to jump in the social media as others do. Her books were selling without her assistance, she retorted. All the while, she was failing to realize the topic of her book was the main reason for sales, a controversial title made it a curiosity and hence books were being purchased. She might have to change her mind one day when future books don't sell as well. In other words, no author should expect current "success" to be the same for every book one writes.
The days of a publisher taking care of all our marketing is over nowadays so authors should do their best to sell their own books, relate to social networks and accept their public persona. Rest assured that a book will sell more when we put forth the effort of selling it and marketing it ourselves.