As you posted this discussoin in 'content writing', I'm going to assume you are talking about writing articles or content marketing.
If you would like to learn how to write, there is no substitute for practice. That might seem simplistic, but there are no shortcuts to knowing how to write, except for the act.
That assumes you are already familiar with proper article format, good grammar and rules of composition. If not, familiarize yourself with those topics first before you start writing.
When it comes to writing, one of the best things you can do is to read magazine articles at both online and offline sites.
By reading these articles you will start to understand the proper elements of an article, rather than simply guessing what goes where.
You might even try to rewrite the article, just for practice. I would not recommend publishing your practice rewrite. Just think of this like a school assignment.
After a few good rewrites, you might be feeling confident in writing your own content.
That's when you need to start compiling a list of good topics for your niche as well as research that will add an authoritative voice to your work.
Once you have all this information, you will want to begin the writing process, starting out with an outline for each article.
Once you are done, edit heavily and polish each line until it reads smoothly outloud.
Just some tips that have helped me over the years as a content creator.