It’s a job. It’s not a hobby. You don’t write the way you build a model airplane. You have to sit down and work, to schedule your time and stick to it. Even if it’s just for an hour or so each day, you have to get a babysitter and make the time. If you’re going to make writing succeed you have to approach it as a job.
I can’t even tell you how many successful authors offer this as a piece of advice.