How to make my paper "less narrative"

More academic is generally going to mean citations. You show a background for what you are asserting. You need to support what you are saying and use formal English, not colloquialisms. This also means contractions are out unless you're quoting someone.

If this is your bachelor's thesis, then isn't it your last paper/project before you graduate? If so, then look at your best work and see what it was like. If it's not, and you're using the term thesis when you really mean the term essay, why not ask your professor what s/he means?

If you're writing about house music, then a brief narrative description about how house music arose should be sufficient. Perhaps your instructor felt that you were writing a history of house music, rather than actually investigating and describing what makes any particular music house music, and what makes it popular.

get a tyle manual for scholarly ritings in your subject.
Also, most academic writing is passive voiced and hardly ever personalized.