To create a pencil sketch effect in Photoshop, follow the steps given below:
- Import your illustration in Photoshop
- Duplicate the background layer and then desaturate it
- Duplicate this desaturated layer and then Invert colors of this layer
- Change the blending mode to Color Dodge
- Apply Gaussian blur filter to this layer
- Make a pencil line of your drawing from the Filter Gallery
- Use Layer Mask to remove extra strokes
- Lastly, add extra details use the Pencil tool.