I can't understand how can i make the monkey tail that looks perfect. Please tell me the method to do this work. I have tried so many times to make it but failed to do so,kindly help me.
With the spiral tool you get the end spiral. That can be too long, but you can delete a couple of nodes with the direct selection tool, if needed.
You must continue the spiral to full length tail with wanted general shape.
The tail has varying width. You can use the stroke width tool or make an artistic brush with the wanted thickness profile. Even a texture image is possible to use.
a simple thickness profile drawn with the pen, used as artistic brush
a spiral, not shortened, it came out as default
extended the length coarsely by clicking few times with the pen tool
smoothed the curve by dragging the corner anchors with the anchor point conversion tool (it's under the pen)
applied a custom artistic brush
The brush was created by drawing the profile shape as horizontal, dragged to the brushes collection and defined to be an artistic brush.