In the end, there is only one thing the writer can do. There is one accomplishment that is wholly under his control. There is only one action he can take to most influence the positive outcome of his pursuit.
Write.
Write when you have a sinus infection. Write when you’ve gotten only four hours of sleep and you keep dozing off at your computer. Write when things at the office are stressing you out. Write when family members are ill. Write when the leaves need raked and the garage needs cleaned out.
Write.
Those demands will be there, and they’ll get your attention soon enough. A successful writer is someone who finds a way to write. Every day. Under every circumstance. No matter what. They write and then they go on about their life.

Or put another way…
There is only one thing that the writer can do to ensure absolute failure at their craft.
Don’t write.
Don’t write when you have a sinus infection. Don’t write when you’ve gotten only four hours of sleep. Don’t write when things at the office are stressing you out. Don’t write when the leaves need raked and the garage needs cleaned out.
You can easily identify these people. They say things like, “It has been a crazy week, and I’ve been too busy to write,” or “I can’t focus. There is too much going on” or “I’ve had no ideas lately,”* or “I don’t have time to write.”
These people are not writers. They are not writers for one reason. They don’t write.
Is the plumber a plumber if he doesn’t daily grant himself the time/energy/focus to fool with pipes?

*Ideas are only generated when you are writing – or are in the daily habit of writing. They don’t arrive willy-nilly through some secret door to which only “creative people” hold the key!