Well, my creative process can vary on track to track. Sometimes I have a melody in mind, or just chords, bassline etc. I usually have one or two musical ideas and hopefully when I put them down I can think of something from that and develop it.
I haven't really got a system or anything, I just go with the flow and sometimes I get cut short and I leave the track for another day (sometimes for a day that never comes) and sometimes I can get the track finished in a day.