One aspect of the beauty of the arts is their ability to invoke strong feeling in those witnessing them. They serve as a reflection of who we are, what our societies value, what we as individuals value. They make us want to be better people. And this is, in part, due to strong performers who are able to create those strong emotions in their audience. A performer must show that what they are doing, be it singing, acting, dancing, playing an instrument, or any other type of performance, means something to them.
When a performer begins to prepare for a performance, they need to understand that some pieces just are too far away from themselves for them to connect to it effectively, and believably. The nature of performance is a universal feeling of closeness, and yet some differences between intended performer as designated by a playwright or songwriter, and a performer hoping to do the piece in question, just cause dissonance. For example, some pieces are written for someone of a particular race or age, and changing this would only make an audience uncomfortable. Of course, it all depends on the performer and the context.
The monologue or scene or song that you have selected, be it for an audition, for a showcase, or some other context, should show the audience (whoever they may be) the core of who you are as a person… what drives you in life. You are metaphorically stripping down and being brutally honest about the person who is there. Putting on airs or trying to be someone/something you are not will only turn an audience off from whatever it is you are doing. And be respectful of others.
Fear won’t get you anywhere. Doubt won’t either. Be willing to bare yourself to the world at large.
You aren’t the only one trying to find an emotional connection with what it is you are doing, struggling perhaps. Plenty of others in the same field as you are going through the exact same thing. And maybe you can’t hit a C6 or interpret Greek drama. But if you make just one person feel something, you will have done your job well.