If you want constant traffic to specific hubs then they have to be niche articles that people frequently search for on the internet. Write SEO friendly articles that people will find easily through search engines.
You also must promote your hubs by creating backlinks and RSS feeds. Articles that are of greater long term interest will also gather more traffic. Such articles include health, technology, arts, fashion and travel. Trend articles are short term traffic generators and will be lost as soon as the trend changes.
For ideas on promoting your hubs for more traffic you can read:
and follow more articles in the same category.