Do I need to be explicitly aware of my theme?

Yes. Else you can't write around it.

That doesn't mean you need to know it at the beginning of the writing process - you can discover it as you go along. But it means that once you discover it, you need to rewrite around it.

There's an advanced worksheet showing how theme works at http://www.kalbashir.com/THEME-Advanced-Worksheet.html

Best,
KalBashir.com