The practice and study of content development may just be the single best way to become a big league copywriter.
In fact, it is now widely recommended by many experts at some of the worlds' leading advertising agencies that students who are diligently putting their 'perfect' portfolios together and refining them every day, ALSO engage as much as possible in content development in order to understand and appreciate that being able to write content in ads is critical for them to learn as they grow.
As they say, not everything's a headline, baby. So being able to develop content and ideas that play out is very important.
Why? Two reasons...
1) Content development builds strong journalistic techniques.
As you continue to develop your content, you will become amazingly better at understanding the value of journalistic writing. This is a format of writing that you have become accustomed to READING but might not understand how valuable a skill it will be when you turn to WRITING.
Journalistic writing is simply the 'upside down pyramid.' In an upside down pyramid, the big section is on top, and it gets smaller and smaller until it becomes a tiny point. Same with your writing. More info on top...less and less as you reach your conclusion.
Throughout your schooling, you have probably taught to 'spread the writing wealth' across all paragraphs and pages. See the difference?
2) Content development flexes keyword density awareness.
These days, with keyword density being such a prominent factor within the algorithms of the search engines, if you've spent days in content development, you will actually make for a better copywriter.
You will start to NATURALLY know where keywords need to be placed, and how often they appear. Basically you need to make them invisible for your human audience and prominent for the search engine spiders.
Journalistic writing is simply the 'upside down pyramid.' Most of the most important information is placed the beginning of the piece and as the writing continues, the paragraphs take on less and less value.
So it should be very clear that content development and refined creation of it that further strengthen your copywriter muscle.