I use iTunes for this and bridge across to rekordbox and traktor. So I create playlist folders and they are by main genre, or how I feel I can find them easier. For example I'll create a folder called house. In that folder I'll have different playlists as the sub genre. So for example I'll open my House playlist folder and inside I'll have Funky House, Disco House, Deep House, Future House, so on and so fourth. I will keep creating folders until my music is sorted, so, I could have another folder called Bass Music and inside that there will be Trap, Twerk, Footwork, Dubstep and so on