I have pretty much everything down when it comes to black metal like the drums, guitar tone...etc but i can't write riffs for the life of me mostly because I don't know to much about music theory. All I know is that half steps, dissonant chords, minor chords, open chords mostly make black metal up while also mostly tremolo picking. The thing is idk how to do these things except go up or down a half step. I tried making riffs but all it ends up being is power chords tremolo picked that sound all off key especially when transferring into another riff. I'd like to make a song thst starts off with arpeggios then goes into tremolo picking open chords but I don't know how to do that.