Develop a habit of working on your habit every single day. No excuses, no exceptions.
The secret to massive productivity as a novelist is to write every day. How in the world can you possible do that?
Read Chris Fox's book Lifelong Writing Habit. It's a quick read, an easy read, and every chapter ends with a short homework assignment. Do the homework and by the end of the book, you'll have a writing habit that will carry you for the rest of your life.