I just try to make something that sounds good to me. It is like organising a space, and the objects in the space are the notes i randomly pick at first, but then if it is required i change them up so they fit into a pleasing progression. Most of the time i try to make unorthodox melodies in alternating time signatures, because the thing that i learned about music, first and foremost, was rhythm and counting the beats. I am untrained, but i am the kind of asshole who would prefer even 3\4 to the standard 4\4. The fact that i am untrained leaves me blind in terms of chords; I don`t know if there is information that can help me with chords, or with making them up on the fly. I can make a major or a minor chord, but nothing else that comes to mind. I just guess what would fit in, sometimes i double the melody in a higher key, i guess.