Make a copy of the layer, change the color of the drawing, offset it a bit, put behind the original then change blending mode to multiply.
What a multitask.Draw big circles and fill the gaps with small ones.
My condolences if you have this in Suika Game.Rough and widen the circles up with the warp tool.Gaussian blur the shadowsPut seashells, sea glass, etc. on a new layer.Put lights and flow on a new layer.Like this