1. Be decisive, choose something, then attack it.

Writing wasn’t London’s first career choice. When he was forced to leave college early after his finances dried up, he needed to do something:

I decided immediately to embark on my career. I had four preferences: first, music; second, poetry; third, the writing of philosophic, economic and political essays, and, fourth, and last, and least, fiction writing. I resolutely cut out music as impossible, settled down in my bedroom, and tackled my second third and fourth choices simultaneously. Heavens, how I wrote! Never was there a creative fever such as mine from which the patient escaped fatal results. The way I worked was enough to soften my brain and send me to a mad-house.

I wrote, I wrote everything — ponderous essays, scientific and sociological, short stories, humorous verse, verse of all sorts from triolets and sonnets to blank verse tragedy and elephantine epics in Spenserian stanzas. On occasion I composed steadily, day after day, for fifteen hours a day. At times I forgot to eat, or refused to tear myself away from the passionate outpouring in order to eat.

The early days for London were a period of restless exploration. He tried everything. But most tellingly, he wrote a lot.

2. Be persistent, endure struggle, and hone your craft.

We all have to toil away in our creative pursuits. But harder than the work itself can be the long period of gestation when it feels like nothing is happening.

The trouble with the beginner at the writing game is the long dry spells, when there is never an editor’s check and everything pawnable is pawned.
Success, though, is a stacking of the bricks. Each one leads to the next, and along the way the technique gets more effortless:

I struggled along, stood off the butcher and the grocer, pawned my watch and bicycle and my father’s mackintosh, and I worked. I really did work, and went on short commons of sleep. Critics have complained about the swift education one of my characters, Martin Eden, achieved. In three years, from a sailor with a common school education, I made a successful writer of him.

At the end of three working years, two of which were spent in high school and the university and one spent at writing, and all three in studying immensely and intensely, I was publishing stories in magazines such as Atlantic Monthly, was correcting proofs of my first book (issued by Houthton, Mifflin, Co.), was selling sociological articles to Cosmopolitan and McClure’s, had declind an associate editorship proffered me by telegraph from New York City, and was getting ready to marry.

3. Develop a routine and be relentless about it.

One key is figuring out what works for you and developing a steady routine. A common denominator of successful creative people is simply pulling the reps.

As I succeeded with my writing, my standard of living rose and my horizon broadened. I confined myself to writing and typing a thousand words a day, including Sundays and holidays; and I still studied hard, but not so hard as formerly… There was so much to learn so much to be done, that I felt wicked when I slept seven hours. And I blessed the man who invented alarm clocks.

4. Settle into a groove and make the act of creating part of your life.

At some point the routine becomes a livelihood. What you do is not separate from who you are. Your day is in service to your craft.

The program of my ranch life was as follows: Each morning, at eight-thirty, having been reading or correcting proofs since four or five, I went to my desk. Odds and ends of correspondence and notes occupied me till nine, and at nine sharp invariably, I began my writing. By eleven, sometimes a few minutes earlier or later, my thousand words were finished. Another half hour cleaning up my desk, and my day’s work was done, so that at eleven-thirty I got into a hammock under the trees with my mail bag and the morning newspaper. At twelve-thirty I ate dinner and in the afternoon I swam and rode.
Jack London wrote some of America’s most enduring stories. He was horrifyingly prolific. Take some cues from his work regime, and get on your own way to building a creative life.

(HT: http://99u.com/articles/7204/call-of-the-wild-jack-londons-advice-on-honing-your-creative-craft)