Best way to convey your specialization?

I am in the process of making a proof of concept for a narrative-driven game which will eventually require a prototype. Not only would this be for a project I'm passionate about, but I want it to also double as a means to improve my portfolio and possibly show my specialties in the field.

My strengths reside in narrative design, writing, environmental storytelling etc. so I need my proof of concept and prototype to reflect those strengths. I plan on creating an interactive flowchart with attached concept art and possibly storyboards. After those are done I want to provide a vertical slice of an interesting section of the game, (perhaps the opening segment with some intriguing mystery) and convey my specialty.

What are some ways you improved your specialized skills (like character design, AI programming, etc.) and how did you convey that in your prototype? Maybe share some unique ways to pitch your game idea or put a prototype on your resume that helped you land your ideal position in the gaming industry?

Any tips or Ideas are appreciated!

-Dylan