Our friend Mr. Picasso said, "Good artists borrow. Great artists steal." I'd recommend you start stealing until you're the best

Kidding aside, I firmly believe that art
is communication. And it's the ability to have a message and communicate it
authentically that makes for good art. Good images make you
know something or
feel something.
And why do they do that?
Because when the artist created it, he or she had something in mind that they wanted viewers to think or feel. Generally for wedding photography this is something like, "this bride is elegant and sophisticated," or "this couple is fun-loving and playful." For senior portrait photography this might be something like, "This young man is thoughtful and artistic," or "this young lady is fashionable."
Once you know what you're trying to say, it's easy. After that it's just technical details. Using your lighting and composition knowledge (and mad photoshop skillz

) to communicate that message. But it's all about the message.
And how do you find that message in portraiture? You have to get to know your subject. You have to develop a personal relationship with this person so they will open up to you and show you who they are. Then you'll show that in your images. That's what makes your images authentic, and differentiates
communicative art from a picture.
And how do you get this personal relationship with your subject? That's easy, Robert Capa told us 70 years ago. "Like people and let them know it."
Oh, and failing all that, just buy a better camera. That works, too