In terms of inspiration, I would say to pick something that at the very least you don't mind spending a lot of time studying. One of the things that helped me with this IA was picking something that I'm passionate about (leaving a zero to low footprint on the environment). Cite as you go, and don't be afraid to reach out to professionals working in the area you're thinking of -- or are -- exploring. Sending emails (some of which were not replied to) was one of the ways I was able to learn more about what I was trying to explore, they both directed me to more sources and helped me become more invested.