I feel as if I make a lot of running analogies when I think about writing. Writing a book is a marathon, not a sprint. Writer's block is like an injury; sometimes you have to do less now so that you can do more later. Setting writing goals is like setting training goals: they push you toward where you want to go and inspire ambition and ingenuity.
However, with running, the results are tangible. You can tell if you're running longer. Or faster. Or winning a race. With writing, you can tell if you're writing more words, sure, but are they any good? Are you getting better? How can you tell?
I don't have answers to these questions and I'm not sure what "better" really is, and unless that's defined, there's no way to know if one is making any writerly progress in that area. Does "getting better at writing" mean:
Receiving good feedback from crit partners/teachers/peers
Getting an agent/book deal
Selling lots of books/getting positive reader response/making a living, etc
Finding pride in one's own growth and enjoyment of the creative process
Gaining confidence in one's writing ability
Developing a strong sense of identity: defining and understanding who you are as a writer
Clearly, the internal are the things we have control over, and which, to me, are the most intrinsically motivating and satisfying. But in producing something creative that is meant to be experienced by others, the external often ends up mattering a great deal. So how to balance the two?
In your own process, how do you define better?