In order to fill a novel with action, you must show, not tell.
Not too long ago, an author approached me to blurb her novel via Facebook for her self-published book. I asked her to send an eCopy of the manuscript so I could read it. I read about seven pages before I had to stop. There was no action, no urgency that set a pace to demand I keep reading. Don't get me wrong, she had great ideas and a strong storyline, but she was telling how a character got from A to B, rather than showing the action.
The novel was tattered with he/she "Began to, tried to, continued to, attempted to, felt," etc. These phrases clutter writing and hurt the pace of any story. In most cases, these can be dropped and tighten up the prose dramatically. And since her novel would be self-published, she didn't have an editor to point this out to her. I explained this to her, based on my own personal experience, and suggested she revise her novel to remove linking verbs to strengthen the action. After all, as I had learned, what you publish puts your reputation on the line. First impressions happen only once.
This is just one of the dangers of self-publication (I plan a future post about the pros and horrors of self-publishing), and why having an editor is very important.
The art of writing is RE-writing. Revision is key. I revise constantly and never totally feel satisfied.