Feature articles are a combination of fact and opinion - bias facts if you wish.
You should get all the facts exact and then add your educated opinion to it.
You use often emotive, persuasive and heart-felt words in the piece of writing. The best way to do this effectively is to get a strong opinion for or against the issue(s)/topic(s). Then you can speak your mind more.
Also, they usually follow introduction, body paragraphs and a conclusion. In the introduction you leave people wanting to read on - leave it kind of unfinished and don't reveal too much in the intro but ENOUGH (be sure to state all the general comments and facts) and make the issue seem interesting to them and revelant to the reader(s).
In the body paragraphs explain (notice I haven't said discuss as you should go for a more one-sided, subjective response with inrefuttable evidence provided from objective sources) you issue in detail trying to cover every argument on your 'side' of the issue. Be sure to include statisitics, personal quotes and any other primary/secondary sources in these paragraphs to inform your opinion and give your feature article a larger degree of credibility.
In the conclusion, try to CONVINCE the responder that what you have just composed is TRUE or at the least a very important viewpoint in the issue you have chosen. In the conclusion, try to give it that perfect cadence, finished feel.
If anyone wants to prove me wrong in some/all of what I have just said, feel free.