Fiction takes forever. One slow word against another.
Tales are told of writers who spend a day to add a single word, as the subsequent day might just be spent removing it. Yes, this happens. Others write in concentrated bursts, and very little after; at least, until the next burst.
The most important writing lesson: patience. The second: learning to recognize what works best for what it is you think you want to do. How to do the writing you do, and do it best. I think my own work a combination of the day spent adding and removing, and the productive, compressed burst. The slow, repeated carve.
Life is too short for long fiction