Most copywriters don't know how to sell...
You can be a great copywriter. Practice writing and designing landing pages everyday. But the prospect won't know that unless you know how to sell. If you can improve your ability to sell, close, negotiate, You can also implement these skills into your copywriting. At the end of the day, It's understanding the psychology and what motivates a person to take action. Want a good book on psychology? If this post get 5 likes, I'll share the book with y'all.