When building a novel, I have found it is much more complicated than simply extending a short story form into an epic form (see Jon Franklin's Writing for Story a good book for writers). When I write and simply let the words flow through my fingers to the keyboard, I ramble. In order to create a cohesive story that runs through a full book-length narrative (and action), I find it easier to think of it like a painting.
First, I have to know the landscape in the background. Not that I write pages of description about the mountains or desert or beach or concrete or traffic, etc. I want to know where and when the action takes place. What else was happening in the world; what were the universally known political events, what was playing at the movies, what were the hit songs, what was the weather like? If the story is placed in the future or an indeterminate time, this still has to be known, even if I make it up out of thin air (I have no idea if people can create anything from thick air).
Next, I want to know about the people. Are any of the characters in the story real people? These can be temptingly easy to use if there is a lot of biographical information available (watch out about putting words in their mouth they haven't said). What about the fictional characters? What do they look like, what are their habits and why do they have them?
Then I want to know about the plot, what is the dramatic situation, how does our hero deal with the journey the story is going to put them through? What is the difference or twist in this story versus similar stories that are already out there and yes, they do exist - originality is found in how you write it differently. If you disagree, read The Hobbit by J.R.R. Tolkien, then go read Beowulf, or Gilgamesh and look at the parallels.
Now, that I can paint these elements, I want to know about the emotional tone, it should float up and down like a biorhythm. I want to make sure I keep the suspense working. I want to peak the reader's attention with a love interest, I want to...
Well what I really want to do is write a book that the reader can't put down, one that they want to tell everyone about.