Draw and paint a tentacle
First I loosely sketch in the basic shapes, playing with the pose until I achieve something on the canvas that I like. Then I sketch in a line to separate the two surfaces. I add contour lines to help me later on with the texture, and rough in oval shapes for the suckers. I add a watery background gradient, and apply diffuse colours and lighting with a basic Round broad brush. The tentacle will be a red/magenta, but the light source from above will cast blue highlights. I’ll pick colour from this with the Eyedropper tool as I paint. I start working smaller, moving around the piece and adding more bits of detail. I sketch a note to remind me of my light source. I add a few specular highlights at a time and use those contour lines to help me paint in the upper surface arm texture.