1. Use the "Pen Tool" to outline the hair and fill it with the middle color of the hair. This will facilitate the subsequent operations of deepening and lightening colors.
2. Click the "Burn Tool" in the toolbox, select a flexible brush with a brush size of 60 pixels, select "Range" as "Midtone", set the "Exposure" to about 20%, deepen the hair shadow position, and The volume of the hair is revealed.
(Tip) Since the system's default number of undo steps is 20, it is easy to exceed 20 when using tools such as deepening and dodging. Therefore, you can create a snapshot of the history before some operations. When satisfied, you can retreat to the snapshot position for easy operation.
3. Click the "Eraser Tool" in the toolbox, select a flexible brush with a brush size of 80 pixels, select "Mode" as "Brush", set "Opacity" to 60%, and set "Flow" to 60%. Erase some color from the edges of the hair and lower the opacity to make the edges appear softer and more natural.
4. Some specific brushes are needed when drawing hair. Let's make a custom brush. First, create a new file, set the "width" to 50 pixels, set the "height" to 50 pixels, and set the "resolution" to 72 pixels/ inches, the background content is "transparent".
5. Click the "Brush Tool" in the toolbox, set the brush size to 1 pixel, select "Mode" to "Normal", set "Opacity" to 100%, set "Flow" to 100%; zoom in on the canvas, and then Draw some irregular black spots on the canvas.
6. Execute the "Edit Define Brush Preset" menu command.
7. In the pop-up "Brush Name" dialog box, name the brush "Hair" and click the "OK" button to complete the brush definition. 
8. Click the "Create New Path" button on the path panel, create a new path and name it "Fa 1", click the "Pen Tool" in the toolbox, and outline the hair path according to the direction of the hair.
9. Click the "Smear Tool" in the toolbox, select the brush you just customized, select "Mode" to "Normal", and set "Strength" to 100%.
10. Open the "Brush" panel, and in the "Brush Presets" dialog box, set the "Spacing" in the brush tip shape to 1%.
11. Make sure that the "Fa 1" path is selected, click the "Pen Tool" in the toolbox, right-click on the canvas, select the "Stroke Path" command in the pop-up menu, and then select the "Stroke Path" command in the pop-up menu ” dialog box, select the “Smear” tool, and finally click the “OK” button to perform the stroke task.
12. Click the "Dodge Tool" in the toolbox, select a flexible brush with a brush size of 150 pixels, select "Range" as "Midtone", set the "Exposure" to about 15%, and lighten the hair. Part color.
13. Click the "Create New Path" button on the path panel, create a new path and name it "Fa 2", click the "Pen Tool" in the toolbox, and outline the shape of the hair, aiming to match the last path There is a difference and a sense of hierarchy is formed. 