How do I turn direction into a real performance?

You can take direction, hear the note, but turning it into an actual performance, making the instruction live in your voice, eludes you. That is the real craft, and the gap is common. Understanding what is asked and embodying it are two different acts. One happens in the head; the other has to happen in the body and the breath. The trick is not to play the instruction; it is to play the truth underneath it. When a director says warmer or more urgent, do not try to manufacture the sound of warmth or urgency. Ask what would make the character actually feel that, then let the feeling produce the read. A note is a destination. Performance comes from finding the real inner reason to go there, so the voice changes on its own rather than being pushed into a shape. Practice this alone with any line. Take one direction, say more tender, and instead of imitating tenderness, imagine a real reason the character would feel it, then speak. Notice how different that sounds from forcing it. Do this again and again, and interpreting direction stops being translation and becomes instinct. You are not failing to follow instructions. You are learning to turn them into something true.