I think what I want to see here is more of a sense of where the light source is coming from. The cast shadow and the highlight on the brown twig would indicate a light from the right. I want to see that highlight and shadow on the grey twig. (I know it is more challenging on a twig with so much texture.) Also try to follow the curve of the twig with your cast shadow. Looking at it closely now, I think an issue is that the bottom edge of the grey twig doesn’t folllow through in a straight line under the brown twig. It curves to the right. I think if you erase that line to make it more perpendicular, the twigs will feel more separate.
I think what I want to see here is more of a sense of where the light source is coming from. The cast shadow and the highlight on the brown twig would indicate a light from the right. I want to see that highlight and shadow on the grey twig. (I know it is more challenging on a twig with so much texture.) Also try to follow the curve of the twig with your cast shadow. Looking at it closely now, I think an issue is that the bottom edge of the grey twig doesn’t folllow through in a straight line under the brown twig. It curves to the right. I think if you erase that line to make it more perpendicular, the twigs will feel more separate.