If you're not in a top writing school - you submit your novel to a publisher and it sits in the slush pile for a few months. You write another novel while you're waiting. When you get the rejection slip, you submit your second novel, and you submit the rejected novel to a different publisher. While waiting for the next round of rejections, you write your third novel. Eventually you get something published. Until then you keep writing and mooching off your spouse.
If you ARE in a top writing school... well... you do EXACTLY THE SAME THING.
Not necessarily. If you know people, they would be willing to agent your work to represent it to larger publishing companies that only take agented work. Then you have a much higher chance of being accepted before you write another novel and then it's simply a matter of giving your latest manuscript to your editor and seeing what they say.
If you ARE in a top writing school... well... you do EXACTLY THE SAME THING.