I recently wrote an answer on Parenting.SE about the process of learning how to read. There are distinct sets of skills that need to be mastered before people become proficient readers, and often recognizing the skills that are being practiced is beneficial to supporting the needs of the reader. In that particular case, the child wasn't demonstrating reading comprehension, but his behaviors suggested that he wasn't quite at that stage yet, and needed practice in other areas first.
In the reading world, this is described as the reading continuum. There is an analogous writing continuum, but because of my lack of experience with writing development, reading about the continuum has left me with these questions (which I'm hoping a literacy or writing teacher can help me with):
How are fundamental writing skills developed?
We have to learn the shapes of letters before we can write words. I'd like a short overview of the skills involved in mastering basic writing (similar to what I outlined in my answer about reading).
How are these skills assessed?
We can see evidence of developing reading strategies through some typical behaviors that are present at each stage of learning. Along with naming the skills, what are some ways that these skills manifest as behaviors I can recognize?
Is there a means of figuring out what areas I am missing, or that need more practice?
I'm thinking of the development of basic, fundamental writing skills rather than developing specific writing styles (technical, creative, etc).