My advice to every aspiring copywriter has always been, “Step one is to listen to your audience”.
Put another way, “If you don’t know who you’re talking to, how can you know what to say?”
When you listen to your prospects and your customers, you get a feel for the emotions they bring to the table.
Identify their fears and desires, and you can speak to those emotions in your copy. Get a sense of the language they use, and you can mirror that language in your own writing.