Simply put, it’s about time. Writing a publishable novel takes a great deal of work and time.
It starts soon after writing a first draft. Many published authors will tell you that they spend as much or more time rewriting and revising as they did when writing a first draft. Getting down the first attempt at your novel is only step one. It must be polished to as close to perfection as possible, and this process can take months or even years. It is almost essential to take periodic breaks from the book. Only during this separation time, of at least one month and perhaps two or three, is an author able to return to the work with somewhat fresh eyes. An added benefit is that during break times away from the book, often authors come up with new ideas and/or solutions to problems that have plagued them about the piece.
The next time management mistake occurs after an author receives feedback and/or an edit. Once a critique and recommendations come in about your work, take some time to let the information sink in. Many times authors dive into revisions without giving due thought to the process and proceed with only a superficial treatment of problem areas in their book. Again, this is a time to sit back and let creative juices flow and the thought process gel before pushing ahead.
And finally, the process of finding an agent and/or publisher cannot be rushed, either. Do research on all agents and editors you submit to and follow submission guidelines exactly. Keep meticulous records and follow up when it is recommended. Take the necessary steps to insure that you get the best representation and the best publisher for your material.