Cool patterns. Yeah, try defining the shapes with lighting as you mentioned, imagine where the light source is and give the pieces highlights and shadows in accordance. That first one is giving a greater impression of depth.
The second one has some layers out of alignment that make it look a little wonky, but deciding on a centerline and forming them all up over it wouldn't take long. Consider adding something beautiful and detailed in the middle where all the roots converge for an exciting focal point. Take the blues and make them darker and less saturated at the edges for a depth pull.
One thing to try: take all the 2d cutouts and turn them into 3d shapes by giving them a faceted look. You could just draw a single line that travels inside the shape from one end to the other, then shade each side of it lighter or darker, then add highlights. That will create greater value range, brighter brights.
You could also try taking photos of yourself or a model and using the warp and liquify tools to distort your shapes over a face or body, kinda like the card you did of Geoff, creating an organic flow in the shapes. Have fun 