OH! I forgot! The ability to combine slabs! For example, have a block that is half brick & half wooden planks. Also, get rid of those pesky, PESKY lighting errors! They can totally ruin a detailed build.
Check out a show called "The Killing". It's a unique murder mystery show. You would expect the average murder-of-the-week type of deal, but it's actually the same murder over the course of a season or more. The first 2 are on the same case & the 3rd (which just ended) is about a new one. The first 2 seasons are on Netflix. Really good. Also, the Walking Dead (ofc.).
My inspiration came mainly from a guy on YouTube called JamziboyMinecraft (link below.) He builds a lot of fantasy/medieval builds. While I don't watch much of his stuff anymore because he only builds in a highly modified texture pack, his early stuff taught me a lot of what I know now. You can still see hints of his style in my own. Another guy who has been a big inspiration is a builder called Keralis (again, link below.) He does mostly modern & showcases a lot of other people's builds, but since I suffer in interior design, he really helps me out. He also does a good bit of medieval.