I am writing a song that is inspired instrumentally by Stairway to Heaven (chord progression) and 3 Libras (key signature of D major). It started with a bassline in my head, and I just worked out a guitar part. I have a couple different lyrics I wrote recently and I'm trying to formulate a melody and just let it come naturally. I can hear rhythms and drum beats in my head, but I have never gotten this far into the song writing process and have had to solve that problem. How do I tie it all together? How do I fill those gaps? How do I give it my signature sound? Note, I haven't started tracking the parts, yet. I'm pretty close, though.