You are doing a great job of drawing the shapes and colors here. What this needs is some addition of shadow and highlights based on your light source to give it that 3 dimensional feel that we are trying to create. If your light source is coming over your left shoulder at a 45 degree-ish angle, the right side of this whole subject should be darker than the left. Doing that will help a lot. You could also try lifting out a highlight toward the upper left of the subject. Your drawing of your shapes, and the colors are very believable, I really want to see you take it to the next level by thinking more about light source.
You are doing a great job of drawing the shapes and colors here. What this needs is some addition of shadow and highlights based on your light source to give it that 3 dimensional feel that we are trying to create. If your light source is coming over your left shoulder at a 45 degree-ish angle, the right side of this whole subject should be darker than the left. Doing that will help a lot. You could also try lifting out a highlight toward the upper left of the subject. Your drawing of your shapes, and the colors are very believable, I really want to see you take it to the next level by thinking more about light source.