Please Note: These are only common assumptions and suggestions about writing a precis. The requirements of such assignments often vary, so please follow your instructor's guidelines.
A precis is an extremely condensed summary of a longer work: whereas a typical summary will cut something down to about 1/5 of the original length, a precis averages about four sentences total. Generally, your instructor will have very specific requirements for your precis, specifying exactly what content to have in each sentence. Therefore, it is always best to follow their guidelines closely, but the linked information about how to write a summary can likely still be helpful in preparing you for writing the precis: