The secret lies in the way you balance these states of mind. You can learn to trust yourself. And when the day of your performance arrives, you know you have prepared, and all of your conscious training and preparation are stored for you by your unconscious. And there is a time for study and conscious analysis and then there comes a time to flow with your unconscious. And in fact the order you go through these states is not even important, and it can even be simultaneous! Yes, your unconscious mind is far more adept at multitasking than the conscious mind, and it's not so concerned with linear connections. For example, if you are deep into working on a project and then leave that to go for a walk or do some other unrelated activity, your unconscious can continue to work on the project for you behind the scenes if you direct it to do so. You can even work on another unrelated project and still have the first one being worked on for you by your unconscious. This works especially well if you can manage to forget all about the first project.
It's been said that to truly create inspired work you need to tap your unconscious mind, where all of your sensory input and a lifetime of learnings have been stored. Many marvelous connections are being made all the time, below your level of conscious awareness. Throughout history, great innovators and creative souls like Leonardo da Vinci, Mozart, Einstein, Charlie Parker, and many others have made reference to experiencing a state where great works materialize without effort, already nearly complete. As if they are being remembered. As if they had already been there. And here's good news...fortunately, you don't have to be Einstein to experience this state and to use it in your own work. The state is easily accessible to all of us.
One key to tapping into this wealth of inspiration is learning to put your conscious mind on hold and just see what happens. A lot of that comes from feeling comfortable enough with yourself to really experience your inner world without resistance. Many find this to be challenging. So how do you do this? Well, it's not magic. For some it comes naturally, or they happened to stumble on it. Or the home environment is more conducive to this state of mind when you are very young. And many need a little help to get there. It doesn't matter. You can learn it.
Hypnotherapy and coaching can help you get in touch with your inner resources. And give you many practical tools to use in real life performing arts situations.
So do your preparation. Practice your instrument, learn your lines, your choreography. But then...when the time comes, trust yourself. Take the leap...and let go.