They all matter

I hear it often said, "Put your melody in the top voice." No. You should put your melody everywhere and put the most important of those melodies where it belongs and put it there because it belongs there.

Everything is a melody, even your drums and your bed of chords. Even the silences you use are part of a melody. A G Dominant Seventh chord leading to a C Major chord isn't a "G7-C", it is a B going to a C, an F going to an E, and a G staying exactly where it is; it is a series of notes coming from somewhere and going somewhere else, even if they came from nowhere. That is all important. Even how long it takes to go from point A to point B and the path it takes to get there is important. Chords are used to help us easily reference a note structure. Chords are not the end goal, the voiceleading of the notes should be the focus.

Put your melody everywhere and know that you are putting it there.