You can find in the forum as well in the exsisting Hubs many hints and tipps how to write good quality articles. Nevertheless I would say that you improve automatically by every new Hub that you write. Its learning by doing.
In addition it is beneficial to socialize with other Hubbers, not only to win many followers, but also to exchange thoughts as well links between the Hubs.
Certainly, if you have one day many hundred or over thousand followers, then readers automatically will assume that you are a good writer even if you are not.
Furthermore also try to think from the position of your reader target group. What do they want to read?
With Hubs that are giving instructions to help others to improve you probably can attract more readers, than just with reporting about something.
Also have always a good structurein your report that enebeles readers to follow easily a topic. Use typography to highlight certain points or phrases.
Well also provide sources to allow users to read more if they are interested.