1.  Pick a fresh issue, not a tired one.
  2.  Consider what position you will take on the issue.
  3.  Think about your readers and the position they are likely to take.
  4.  Do basic research and list the arguments on both sides of the issue.
  5.  Formulate your claim (thesis):  take care not to be simplistic or extreme.
  6.  Write a rough outline organizing the points you will include.  Do more research as necessary.
  7.  Write a draft.  Include the reasons for your claim and also include concrete evidence in support of those reasons (facts, statistics, incidents, examples, testimony from experts).
  8.  Include opposing views and refute them.
  9.  Use valid and reasonable arguments and provide relevant evidence.
10.  Avoid flaws in logic.