[pafufta816]

the way i mix melodically is by ear. i usually figure out the key a track is in with my guitar, or find a good tonal centre of the piece. next i find another track in a complimentary key.

the great thing about mixing based on tonal similarities between songs is the possibilities.

i.e. if a song is in E, and you want to mix something in that is tonally similar you could choose something in E, A or B and most likely avoid dissonance or tone clusters. also F#, C#m, G#m might work, especially if non-diatonic pitches work.

if a song had a monotonal bassline in D, you could mix in another song in E. the unresolved mix of tones might incidentally have an interesting effect (if the song in E had a G# note in it, the collision with the D bassline might give a nice tension).