take aways:
--organization: i would encourage you to take a simpler approach in a piece such as this (here, you've got effectively two introductions, a meta paragraph on the current piece, a 2-paragraph return to writing assignments mentioned in paragraph two; and a conclusion that aims to wrap everything up in a tidy bow.
--audience and collaboration: given the impact others can have on your writing (the writing guru, for instance), I'm not sure you car metaphor holds up. that gist of the picture you're painting is that writing is a solitary practice (like driving), but your description of the practice of writing seem for your interactive and, to a degree, dependent.
--phrasing: i think you'll benefit from our work on word economy, meta-discourse, etc.