Writing takes time

Find out when is the assignment due and devise a plan of action. This may seem obvious and irrelevant to the writing process, but it's not. Writing is a process, not merely a product. Even the best professional writers don't just sit down at a computer, write, and call it a day. The quality of your writing will reflect the time and forethought you put into the assignment. Plan ahead for the assignment by doing pre-writing: this will allow you to be more productive and organized when you sit down to write. Also, schedule several blocks of time to devote to your writing; then, you can walk away from it for a while and come back later to make changes and revisions with a fresh mind.