There are only 5 steps to convert your Photo to Pencil Drawing.
STEPS:
Step 1: Open the photo that you would like to convert into Pencil Drawing in Adobe Photoshop.
Step 2: Press the short cut key Control + J key (CTRL + J) to duplicate the layer. After that, press CTRL + U and decrease the saturation value to -100.
Step 3: Press CTRL + J again to duplicate the layer and press CTRL + I to make negative effect.
Step 4: Then choose the layer style to Color Dodge. You won’t see anything now (all become white).
Step 5: So, to view pencil strokes (or) depth of pencil tones please apply a Gaussian Blur (From Menu: Filters › Blur › Gaussian Blur) to the top of the layer to become a pencil drawing. Hence, the more you increase the pixel value they more you will see the dark tones of pencil strokes. If you want to have thin sketch lines (soft tones) .. please use lower pixel value.
NOTE: To see the effective result please check the Preview in Gaussian Blur Dialog box.