to be prolific. This may seem counterintuitive, but it really is important. By focusing on such a goal, it could become very easy for someone to lose sight of the reason(s) one writes. Those who read a lot have certainly found this: Some authors who seem to write an encyclopedia's worth of books in a given year lose the quality of their writings over time, so while they may still be prolific, whatever their initial reasons for writing could be getting lost in the quest for higher profits for their publishers, greater fame for themselves, etc. Yes, money and fame can be good, but those goals are probably going to cause more issues than benefits in the long run – if quality drops, for example, fewer people will buy the books, which could put that person's writing career in jeopardy. Therefore, one must focus on other reasons – like the initial reasons – for writing and continually tap into those reasons to maintain a steady stream of output over time.
Related to the above is to never lose sight of the reason for writing. Personally, I simply enjoy it, in part because it is a great way to "forget" the issues and stresses related to my job. Writing also allows me to relive some experiences, and dabble with new concepts. Perhaps a side benefit of all this is that I am almost never bored: When things are slow, I can always think about whatever stories are currently in progress, or consider new stories to be written, so that I am always "writing" even when I am away from my laptop and do not have pen and paper on hand.
Inspiration simply cannot be overlooked. Personal experiences and interests can be a great source of inspiration, and once one thinks about personal interests and the various details and facets of them, for example, the number of stories which can be told could potentially be innumerable. Experiences and interests can also be "combined" in various ways to create new stories. For example, I love auto racing and video games, so I turned the final lap of a racing game into a story, from the point of view of the driver in the car as if the driver was in a real race and not a digitized environment. Using that same combination of interests, I have an idea for a story (which I have yet to map out on paper) in which the characters within a video game try to understand why things suddenly go dark all the time and then their next memory is of starting at the same places and situations when the darkness recedes. There are likely other permutations of the racing/gaming interest combination which would yield interesting stories.
In the end, what really helps a writer to be prolific is to have a strong character or set of characters which practically live in the writer's mind and take on lives of their own. Unfortunately, I have yet to understand just how such characters are created or why certain characters tend to have such a lengthy "lifespan" in terms of the stories they can tell. Yes, this can lead to lengthy tales with dozens of sequential chapters, or perhaps dozens of standalone stories featuring the same set of characters. It is usually easy to recognize when such a set of characters exists, for suddenly the end of a story featuring those characters is no longer the end of