There are of course many ways to do it and to look at it. I have developed my own theory and want to share it with you in this place.
When I compose a song there are three ways of working, three sorts of process:
1: The idea first approach.
I have an idea and want to realize it. So I just start to work and try to realize my thoughts. That’s actually quite easy if I know the neccessairy craft to realize what is in my head. This happens almost never!
2: The creating by doing approach.
In this case I have no specific idea, but just feel that I want to make some music. So what I do is, that I just play around with any kind of instrument. I record a couple of tracks in a 16 bar loop, create a beat, a bassline, genereate a couple of freaky noises or any effects I can use in the background. The loop just goes round and round and all I do is playing around with it till I get a good feeling. So all I do is to try and to feel. Try and feel, try and feel. This way ANY patient person can make music. The heart is the compass. After a while I have a nice loop and I go on and do some more loops with similar sounds, beats or melodies and try to stick to or build on the main feeling. Mostly these loops fit together very well and in the end I arrange them to a song.
3: The mixture of 1 and 2
I have not really an idea but a theme. For example an experience which I want to express in a song. So I do exactly what I described in 2 but all the time THINK of this experience. Automatically my feelings influence the music I play and the song finally describes my feelings in this experience. It’s really magic!
But this does only work if I always listen to my feelings by keeping and not keeping elements created in 2 or 3. If my head decides the song will be without emotion.