April is all about ways to make money writing. J is going to sound trite. But it's not. It's tried and true. Just keep writing. You don't finish that book? Guess what? I guarantee you won't make any money off of it. You won't even learn from it.
Royalty checks come. Some months.
Other months? Nothing sells. No royalties.
But the only way for the next book to sell better is for the next book to be written. Just keep writing.
How do you stay motivated and persistent through the ups and downs?