When you write articles for syndication, they don't have to be as long or comprehensive as the articles that you find in featured columns in magazines.
Concise and useful are two keywords that you must keep in mind.
The problem is, how can you deliver good information in such limited space? Not that there is something wrong with longer articles.
They provide more insights on different aspects about a topic.
Featured articles in magazines is different from long-winding articles.
They must be compact, interesting and contain good information at the same time.
Articles for syndication are different.
They have to be focused on specific topic.
They must convey the information they carry in as little time as possible.
If you focus on one specific thing at a time and discard the rest, you can write convey any ideas in 300-600 words.
Sometimes I include a story in the beginning of my articles, but rather than giving the complete story, I give the short and to the point version.
Many writers should agree that it takes more time to write a concise article than long article.
If you must cram a lot of things in so little space, you must choose carefully what to write and discard the rest.
The situation is a bit different for this kind of article writing though.
It is not about delivering a lot of information in 300-600 words but to focus on that thing only.
If you find yourself adding irrelevant content, you can cut out the article and use that for another article.
You can use existing article skeleton to keep the content focused.
Practice makes perfect.
Once you get into the habit of writing concise and useful articles, it will become easier.