First of all, what is an anecdote? By definition it is a short, personal account of an incident or event, a way of personalizing an article or essay to make it more entertaining and more engaging. These mini stories are a great tool, but be aware; they must be placed carefully in your writing and used to help the reader understand more clearly what you are trying to say.
Where to find them? Of course, they don't fall from the sky or just magically appear. You have to seek them out. People are a great resource. They have wonderful stories to tell and most everyone enjoys talking about themselves, don't they? So, interview! Find some of those interesting people and start taking notes. (Although I'd use a recorder myself. Notetaking is too chancy; you might leave out the good parts!) Another source is the written word – books and definitely primary sources such as diaries, letters, etc. from famous or not-so-famous people. You can find valuable gems in those places.
What to do with them? Placement is key. In the middle of the article is common, but really, you should be the judge and plop it in where it seems to fit. Personally, I like to see them at the beginning of an article because this engages my interest right away, gives that personal touch to where I identify with the topic. More than likely, I will want to go on and finish the article because of that anecdote. You might even take half of the anecdote, place it at the beginning, but leave it as a cliffhanger. When you get to the end of your article, finish it up, rather like a grand finale. As far as constructing your anecdote, be concise – you don't want your reader to lose the true point of the article and stray away. And though you may be writing a non-fiction article, the anecdote should sound fictional. Be creative as you write your mini story. Over all, your anecdote needs to match the point of your article. It must be relevant and fresh. Choose wisely and write effectively.