There are a lot of tips and strategies that people suggest and use for doing what it takes to write an epic novel, but no matter what fine point or strategy one chooses, no matter what preference one tells you or secret one has for writing that book, it really comes down to three simply words.
1) Discipline: Keep a regular schedule or you will never finish that book. regular writing sessions, same time on whichever days of the week you designate to write on, just keep it up and do not let anything distract you.

2) Organization: Plan ahead and keep those notes. Before you begin a book, outline it, know where you are going, then plan out each given chapter before starting it. It’s okay to fly by the seat of your pants from time to time but you still have to know where to start and end. This will also reduce that dreaded Writer’s Block. Also keep notes on your characters and plot developments as you go along.

3) Enthusiasm: You MUST love what you are working on. If you don’t like what you’re writing, then how do you expect the reader to? I don’t care what the market says is “in” that year, choose a genre that you love and you will do your best, not to mention those long writing sessions won’t seem so long.

Discipline, Organization, and Enthusiasm. That’s really all you need. The rest are just details.