Now for the ribbons. Using the Pen Tool create a curvy shape. Fill it with a beige colour (#dcd2b1). Burn (O) one edge to suggest lighting. Duplicate the layer (Cmd/Ctrl+J), select the Free Transform tool (Cmd/Ctrl+T) and adjust the rotation point by dragging the crosshair in the centre of the transform box to a far corner of your element. Now rotate to achieve desired look. Continue this two or three times. Create additional ribbons varying the size, shading, and orientation. The idea is to complement the flow of the model.
To divide the piece more, you can add a coloured shape flowing downwards. Use the Pen Tool to create a mountain with concave slopes. Make certain to overlap the white elements. Load the path as a selection and fill it (G) with another beige colour. Right click the layer in the Layers Palette and select Blending Options. Tick ‘Gradient Overlay’ from the Gradient drop-down menu, select ‘Foreground to Transparent’, change the colour to White, then tick the box ‘Reverse.’ You can also add a texture to this part using the Pattern Overlay feature.
The mountain can stand to use some more dimension and depth. Use the Magic Wand tool (W) to select it and create a new layer (Cmd/Ctrl+Shift+N). Using the soft-edged brush again, paint some black along the left and right edges of the selection. Do this gently and make it look very natural. You can also use Blending Options>Inner Shadow, but I feel this has a more authentic look. Adjust the opacity so the black doesn’t look too harsh.