As an artist I found that I was more likely to finish a painting of something I was interested in than a topic I wasn't.
For me it is the same with writing, because writing a good article requires that the author be an 'expert' in the field they are writing about, research is mandatory for the completion of any 'good' article. However research can be boring, so picking a topic that will hold your interest is essential.
What most authors aren't conscious of when writing on any topic is that the reader will instantly know if you 'know' what you're writing about or are just regurgitating information from another source. Because of this one must be able to put into their own writing style the definition of any concepts, ideas or information pertinent to the article.
This leads back to picking topics that you like and will become familiar with however in this day and age of instant access to a plethora of knowledge you maybe unfamiliar with there is no excuse for anyone not to become an overnight 'expert', providing of course you have a brain and no how to use it.
If you read one of my articles you will know that I have researched my topic and have a precursory understanding of the information I describe. This biggest obstacle I have faced is learning to edit the material and not overwhelm the reader with too much information.
In other words do not insult the readers intelligence by promoting your own, hope that helped.