Make sure you have a thorough understanding of the requirements at the outset of your process.
Spend some time taking a good look at the writing prompt.
While assignments vary greatly, the prompt is a place to hone in on the action verbs that will help you understand what you are being asked to write. Look for words like research, synthesized, analyze, argue, present, defend.
What resources are you being asked to used to complete you assignment?
Know up front exactly which types of resources your professor would like you to use and how many of each (if specified).
Try and spend time reading up on your topic before formulating a thesis or research question.
Now that you have a clear understanding of you assignment, you can spend time gathering enough background knowledge to begin your research and writing.