I think it's important to be prepared when you're a beginner, but then slowly, as you gain experience, let it flow naturally. However, in initial calls, be prepared. Complete your homework. And no, don't try to pitch your services on the first call. Just listen to them, their problems, their pain points, and what solutions you can offer them. You should be thinking about easing their problems through the skills you possess, not pitching your services. When you think like this, you'll gain something far more valuable than just clients.