The classical system. The system of argument often followed by ancient Greek and Roman orators is now referred to as classical. You can adapt the ancient format to written arguments as follows:
Introduction
Gain readers’ attention and interest.
Establish your qualifications to write about your topic.
Establish common ground with readers.
Demonstrate fairness.
State or imply your thesis.
Background
Present any necessary background information, including relevant personal narrative.
Lines of argument
Present good reasons (including logical and emotional appeals) in support of your thesis.
Present reasons in order of importance, with the most important ones generally saved for last.
Demonstrate ways your argument may be in readers’ best interest.
Alternative arguments
Examine alternative points of view.
Note advantages and disadvantages of alternative views.