This is how I start my composition!
I gather my ideas and nut them out in my head and then start placing shapes/tonal and blocking in. I may do a few rough outs early on or else I may just go straight in on the paper/canvas and aim for this to be the final artwork
As I go forward I often find by building the composition I may also get fresh ideas and it will come to life differently as to how I originally envisaged. This final piece for TREE OF SECRETS had some other compositions sketched out of very different ideas; see sketches.